R is indeed comprehensive and extensible, but some people find it difficult to learn.
The most "user-friendly" and intuitive software I have ever used for biomedical statistics and graphing is GraphPad Prism. It has versions for Mac and Windows, and it is currently at version 7. It is commercial software, but I believe it is worth the price. If you are in a university, your institution might have a site license or at least you can get an academic price on the license.
Dear Ahmed, you can try BioVinci. It's easy to use. You just need to drag and drop columns to perform statistics. It's now 25 bucks for one annual license. I think it's worth it. You can download it at https://vinci.bioturing.com
James' suggestion of BioVinci is intriguing. BioVinci is rather new, and it would appear to have considerable potential for data visualization, graphing, and statistics. It uses "R" as its "engine", and provides a way to edit graphs interactively. However, based on my rather brief testing, I would say that BioVinci will require much more development before it would have the statistics capabilities of SPSS. Moreover, as a graphing program, it currently lacks the intuitiveness and feature set of GraphPad Prism or Origin Pro. On the other hand, as James said, BioVinci is easy to use and very inexpensive, and I will be watching the evolution of this program with great interest.
For biostatistics software that is easy to use and relatively cheap, Ahmed might wish to try Minitab or Statistica. These are available at low cost to students and faculty through OntheHub, and some universities have site licenses.