For a nice overview of possible Landsat-8 (and other satellites) indices see here: https://www.indexdatabase.de/db/s-single.php?id=168 - over 100 combinations are described along with their respective citations.

http://landsat.usgs.gov/band_designations_landsat_satellites.php

"Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) images consist of nine spectral bands with a spatial resolution of 30 meters for Bands 1 to 7 and 9. New band 1 (ultra-blue) is useful for coastal and aerosol studies. New band 9 is useful for cirrus cloud detection. The resolution for Band 8 (panchromatic) is 15 meters. Thermal bands 10 and 11 are useful in providing more accurate surface temperatures and are collected at 100 meters."

Thermal band 11 isn't good for processing beacause of Landsat Calibration Notices.

Hi, this is depending what do you want to extract and analyse. Band 1 is dedicated for aerosols, 9 for the cirrus, 8 (panchromatic), 10 and 11 (TIR) You can use the spectral bands 2 to 7.

If you mean composite images for visualization, you can use all bands except 1, 8, and 9 (1 may be useful for coastal areas though). Band 8 can be used to pansharpen the images if you want to make 15m resolution composites (instead of 30m). Here are some common band combinations for Landsat 8 composites (http://landsat.usgs.gov/L8_band_combos.php).

thank you all

the purpose for that to produce land cover map. So in this case which is better to use the bands (1 to 9) or (2 to8) or (2 to 7)?

For a land cover map, 2-7.

thank you all

For land cover mapping, the reflective bands 2-7 are commonly used. True color composite is RGB: 4,3,2; standard false color composite RGB: 5,4,3 and short wave color composite RGB: 6,5,4. Bands 2-7 of OLI are almost the same as bands 1,2,3,4,5 and 7 of Landsat TM/ETM+. The difference is in quantization level only. Most techniques used for Landsat TM/ETM+ can be now applied for Landsat 8 OLI.

is it correct to convert the original bands (Digital number format) to Reflectance and the applying the sun elevation angle correction, then making the final composite?

Thankyou all

For analysis Yes. You better to convert DN to reflectance corrected by the sun elevation, computation of NDVI for example. For visualization you do not need to make conversion at all. But if you do atmosferic correction, the contarst of the final composite image will be maybe better. 

yes actually this is what I did.  I've converted the DN to Reflectance and then I made the sun elevation correction then I made the final composite.

But I saw in some reference that they convert DN to Radiance. whats the exact benefit and what the difference comparing to the Reflectance?

For single scene analysis there is no benefit to make conversion from DN to radiance. However, when you do, for example classification over large area (multi scene analysis) or image mosaic of several scenes, then conversion to radiance and furher radiometric correction is strongly recommended. Reflectance is must when you compute index, for example NDVI, EVI etc., because all these formula are based on reflectance. For composite image of single scene you can you straight the DN. 

Many thanks for you all for the nice discussion and answers

Please have a look at this as it might be helpful:

http://blogs.esri.com/esri/arcgis/2013/07/24/band-combinations-for-landsat-8/

See the USGS site: http://landsat.usgs.gov/L8_band_combos.php . 

You can compare the bands of Landsat 8 with previous sensors bands like L7 or L5 and identify the bands that you need to compose the image. According to the type of analysis, you can use certain bands or you can compose an image with all the bands and then apply principal component analysis, for example, to detect those bands that have the greatest differences and use the resulting image for further analysis.

Visit the USGS site and read about details

FWIW, I have created a comparison table of Landsat 5/7 and Landsat 8 bands at http://courses.neteler.org/processing-landsat8-data-in-grass-gis-7/#The_bands_of_Landsat_8

http://courses.neteler.org/processing-landsat8-data-in-grass-gis-7/#The_bands_of_Landsat_8

Sorry I can't help much, but in BILKO which I am using it seems one can only use 3 bands at once.

I have two questions, if anyone can help I would be most grateful. I am running BILKO  3.4 under Windows 7.

1. Which 3 bands are best for coral reefs and seagrass beds (the same set if bst for both or two different sets)

2. How can I output my results in BILKO with coordinates (a grid or some marker) and a legend (preferably also a title)

I have been seeking for the answers online myself  for weeks... representing many hours of searching over a slow connection with many cut-outs and power cuts.

Have a look at this as well:

https://www.esri.com/arcgis-blog/products/product/imagery/band-combinations-for-landsat-8/

For a nice overview of possible Landsat-8 (and other satellites) indices see here: https://www.indexdatabase.de/db/s-single.php?id=168 - over 100 combinations are described along with their respective citations.

4,3,2 is True color composite (RGB): standard false color composite RGB: 5,4,3

dear it is based on your project

I agree with Hayder, it depend of your project