If you want the fastest for your money, then depending on stock, the X2 6000 is still a brilliant cpu - it runs at 3Ghz and is dual core. If you want newer technology then you could go for the Phenom but in your price range the only one you could get is the triple core 8450 which runs at 2.1Ghz but is about $10 more. Lastly, if you want lower power consumption, then you could go for the Athlon X2 BE 2400 which runs at 2.3Ghz but uses loads less power. Don't forget to get decent ram to go with it tho - 2Gb is the minimum I would go for and get decent PC-6400 speeds or higher if you want to overclock.

... is anything made by Intel.

I used to like these guys (who doesn't champion an underdog), but have had too many compatibility problems over the years. Not to mention their abysmal environmental record. Add to that their purchase of the most difficult video card manufacturer to work with, blah blah blah.

Any chance you could take that mobo back?

Good luck!

Phenom is the fastest graphic cpu with unreal engine 3 games, and there are alot coming, that uses all four cpus for gaming. Otherwise get he fastest dual core Athlon X2 you can afford.

"The computer will be used for email and some word processing, digital photos, and also be used as a HTPC computer."

i would recommend an athlon x2 4850e, it should be less than $100, and has very low power consumption (around 45W TDP if i'm not mistaken). you wont need a powerful,noisy cooler..which is excellent for htpc. also, its powerful enough to handle most loads, and if you ever need more power, you can easily overclock it, unlike the phenoms and the more powerful x2 6000+ and above.

i believe there are a couple of reviews out there pairing the 4850e with a geforce 8200 chipset motherboard (which the an78gs is using), you might wanna check those out.