My two cents:
Short answer: For a budget gaming rig, this looks fine.
Long answer:
- I noticed that no maximum budget was given
- I noticed that no example games were given, and different games benefit from different upgrades
- A 3.7 GHz dual-core is pretty good for games that don't take advantage of multiple cores very well; an upgrade to an i5 would give better performance for a wider variety of games
- As has been mentioned, the PSU is adequate, but buying a better one is money well spent in the longer term because then you can keep the PSU when you do upgrades instead of buying another one (or buying another one when this one fails)
- Getting a motherboard with 4 RAM slots might be a good idea as having the option for adding memory doesn't just provide more memory, it bumps up performance to have 2 or 4 sticks of RAM rather than one (e.g. get a 4-slot MB with 2x4GB then add 2x4GB later)
- I wouldn't worry about mixing and matching brands
- Of course, a bigger HD and/or SSD never hurts!
- Buy stuff from Trevor ;-)
Kevin