I don't think you would really notice a huge difference between a 10k or a 7.2k hdd. Honestly, in your case its not worth the price difference. The 10K drives are very popular with gamers though.
You should get something with around 2 gigs of RAM or more, but honestly, 2 gigs will do you just fine. You should get a video card, but nothing special. This is just useful for your photoshop needs.
You should also get something with a decent processor. I recommend that you go core 2 duo, and get at least the e6600 processor. Its powerful and will meet your needs.
I don't know how large your programs are, but I know that compiling is mostly processing and RAM oriented which is what you want your focus on. I really don't see what you need such a fast HDD for.
If you know how to build it yourself, save yourself some cash and do that, trust me its worth it. if you don't know, then you can look it up, its very easy to learn. If you must get a prebuilt one search for prebuilt ones with stats such as above