I build a system a few years ago and I feel as though its getting dated. I'd like to build a new one and pass my old one along to my little brother as a gift to him for the summer, but I'm seriously out of the loop on the new technology and compatabilities.
From some very minor research I've found that either the Intel E8400 or Q6600 seem to be the processors to go with, but thats only a small portion of finalizing a PC.
If someone could make me some suggestions on a solid gaming PC for no more than $1500 that'd be great.
Well... if you want us to build it for you just say so. Otherwise with what you've posted so far all I can really say is that both of those procs are good choices. With the Q6600 coming down in price and support available for it it's a good option. It's a great overclocker too. The E8400 is one of my particular favorites being one of the fastes duals available. I would opt for one of them if you like to overclock and game. A Q6600 might keep you going for a few years though. However being so old I would look into the Q9300 maybe.
A good motherboard is the next step. X48 chipset from Intel might be a good place to start. The P35 chipset is also great "proven" performance. If you want dual Nvidia cards like I did the 780i/790i are great boards. I like companies like Asus, EVGA, MSI, and gigabyte. Also I would buy DFI, and Abit. Stick with those companies and one of the metioned chipsets and you should be good to go.
For GPU the 9800GTX is coming down in price and is a great performer. If you are on a budget you cant beat the 8800GT price right now.
Memory... Get whatever your board specifies. A good 2X2gb set of DDR2 800 or DDR3 1333 should get you started dependent upon what board you get (X38/X48 come in DDR3 and DDR2 flavours while 790i is specifically DDR3... Foxconn X38A is a board that gives you options)
Good luck and keep on asking!