JLV2k5 [Just because the guy has a $2800 budget it doesn't mean use it all and waste his money]
Don't get 8 gigs of RAM like kungfumosquito has suggested. You do not need that for a gaming computer, 4GBs will suffice. He also does not need a $200 or a $140 sound card. A basic SC or a motherboard will good onboard sound will do for most gamers. I agree with the majority of the other selections made by kungfumosquito. Although, I like the Logitech G5 gaming mouse personally. If this is primarily a gaming system, the guy probably will not need 500gb of HDD space, so money can be saved there. And i dont know what DVD drive he picked out($80????), but i see lots of standard R/W DVD drives for like $30.
This will substantially save some money, hope it helps.