This is a very interesting question.  I think it depends on what you want to do with the body scientifically and what you goals are.  Here are the 15 ways that I know of to handle the human body after death, and some of these surely have subsets:

1.Aquamation is the most environment-friendly way of disposal of human bodies. The process involves the rapid disintegration of the human body into high quality fertilizers. In comparison with cremation, about 10% of the energy is used, and all of the associated pollution is avoided.

2.Burial is the act of interring a person or object in the ground, and is probably the simplest and most common method of disposing of a body.

Burial is generally accepted to be one of the earliest detectable forms of religious practice, and many hominid remains have been discovered interred with grave goods, or with obvious signs of ceremony. Even today, most burials are presided over by a religious figure, and in many cultures they are conducted with great reverence.

3.Burial at sea is the term used for the procedure of disposing of human remains in the ocean. Many cultures have regulations to make burial at sea accessible, and it is fast becoming a popular choice. In the United States, ashes must be scattered no less than three nautical miles from the shore, and bodies given over to the sea must be buried in locations of at least 600 feet depth.

4.Entombment is the act of placing human remains in a structurally enclosed space, or burial chamber. This differs from burial in that the body is not consigned directly to the earth, but rather is kept within a specially designed sealed chamber. There are many different forms of tombs, from mausoleums (specifically built for this purpose), to elaborate (and often decorative) family crypts, to a simple cave with a sealed entrance. A mausoleum is typically an above-ground structure, but a tomb may also be an underground chamber.

5.Dismemberment has been practiced in the past on the bodies of Catholic saints, as their earthly remains are considered to be holy relics.

6.Cremation is the process of reducing dead bodies to basic chemical compounds in the form of gases and bone fragments. This is most often performed in a crematorium, though some cultures, such as India, do practice open-air cremation. Generally, temperatures of no less than 1500oF are required to ensure complete disintegration.

7.Space Burial in the late years of the 20th Century, it became the vogue to be “buried in space,” that is, to have a small part of the cremated remains placed into a capsule (about the size of a tube of lipstick) and launched into space using a rocket. Since 2004, there have been about 150 space burials.

8. Mummification has been practiced for years.The Egyptians are perhaps the best-known adherents of this process (although they are far from the only ones), in which a corpse has its skin and organs preserved, by either intentional or incidental exposure to chemicals, extreme cold, very low humidity or lack of air. The oldest mummy found to date was a decapitated head that dates back to 6000 BC. The earliest Egyptian mummy dates back to about 3300 BC.

9. Cannibalism also known as anthropophagy, cannibalism has been recorded throughout history and continues to be practiced even today. Specifically, it is the act of humans eating other humans. If humans are specifically killed to be eaten, it is called homicidal cannibalism. If the practice is restricted to those already dead, it is called necro-cannibalism. There are two kinds of cannibalistic social behavior: endocannibalism (the act of consuming humans from the same community) and exocannibalism (eating humans from other communities).

10.Cryonics is the low-temperature preservation of humans and animals who can no longer be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Because, in the United States, cryonics can only be legally performed on humans after they have been pronounced legally dead, procedures ideally begin within minutes of cardiac arrest and use cryoprotectants to prevent ice formation during cryopreservation. However, the idea of cryonics also includes the preservation of people after longer post-mortem delays because of the possibility that brain structures encoding memory and personality may still persist or be inferable. Whether sufficient brain information still exists for cryonics to work under some preservation conditions may be intrinsically unprovable by present knowledge. Most proponents of cryonics, therefore, see it as a speculative intervention with prospects for success that vary widely depending on circumstances.

11.Dissolution is a tried-and-true favorite of those who really want to make certain that remains are never found: simply dissolve the body in a strong solvent, such as lye or hydrochloric acid. Unfortunately, it’s not quite that simple.

12.Exposure is not typically practiced intentionally in the West today. More often, it results from an accident where someone dies in an isolated location and the body goes unnoticed for a period of time. However, there are people who dispose of bodies in this manner on a regular basis.

13.Mass Grave have been used when expedience is an issue, as is often the case with a plague or a disaster, a mass grave may be used. A mass grave is simply a singular location in which multiple human remains are interred. Mass graves are common as a result of wars, plagues, famine and disasters, when health concerns become an issue and it would be unwise to wait for each body to be identified and given the proper rites. Mass burial is generally frowned upon because it detracts from the identity of the deceased.

14.Taxidermy is the act of mounting, or reproducing, dead animals for display (e.g. as hunting trophies) or for other sources of study. However, some people haven’t let that stop them from taking the next step to immortality and having themselves taxidermied after death. The process is rather simple, but requires a lot of skill. The animal is skinned and the innards disposed of (often without the taxidermist ever seeing any of the internal organs). The skin is tanned and then placed on a polyurethane form. Clay is used to install glass eyes. Forms and eyes are commercially available from a number of suppliers. If not, taxidermists carve or cast their own forms.

15. Plastination is perhaps the ultimate bid for immortality, plastination is a technique used in anatomy to preserve bodies or body parts. The water and fat are replaced by certain plastics, yielding specimens that can be touched, do not smell or decay and even retain most properties of the original sample. The resultant plastinates can be manipulated and positioned as desired.

brilliant and outstanding answer , i never dream of that Mr. Brian

my targets are:

1-human dignity.

2-keep some tissue for further scientific development to make use of remaining tissue to renew life

I 100% agree with you.  That being said all 15 of the  ways can be interpreted as the perfect way to accomplish this based on who you are talking to.  Good luck

but for the time being can we reserve some bone marrow stem cells in mega-bank in liquid nitrogen  during life to be used later and at the same time we try to use the most logical method to keep body dignity?

I think that is a great option at this time.  In the research I have read the general agreement is that stem cell viability is maintained from 14-17 days after death.