Everyone seems to forget the psu(power supply) and is taken for granted. All too often supplied with a new case while they work, may not for long or be underpowered. A decent system needs a good psu in order to remain stable and provide steady outputs. If you plan not to get into heavy gaming and generally a typical home system, a 500W+ psu will do fine. There are cheap offerings out there in the 500W range and when you look into the matter see the difference price makes and what will suit you. I take it seriously the lack of a decent psu in new systems, because of the reasons above. Everything else you mentioned seems OK. Use common sense and proceed, good luck.
Im going to need a PC that will run a few apps and probably a couple of games that dont require high-end graphics. I looked around and came up with these specifications:
Intel Core 2 Duo [2.6 GHz]
DDR2 Ram [2 GB]
Hard Disk (sata) [250 GB]
Graphics Card [256 MB]
Now, I'd like to know if this will do the job and also if there are any additional things that I'm going to need other than a case.