Heres a decent Mobo/RAM combo:
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.493086
The 790X chipset, (this board specifically) will get you a lot of the bells and whistles that the 890GX boards offer, but at slightly less cost. If your looking for something more suited for overclocking, crossfiring/SLI (hack with AM3 boards), and more intense gaming, I'd look at a 890FX or even 790FX board.
But that leads me to ask, what kinds of games are you playing? If you play on your 22" monitor, your resolution is (correct me if I'm wrong) 1680x1050? At that resolution, you could get away with a card like a 5770 and play things fairly well (like myself) for around $160. You could spend $20-$30 more and get a 5830, which would be a big bump up, or you could spend between $200-$230 for a GTX 460, which has been dubbed the best card for that price/performance in that general area. But then it comes down to your budget as well. If you want/need a quadcore for gaming, I'd say go with the Phenom ii 955. But AMD offers plenty of options for an AM3 socket gaming chips. I love my 550, but if you have the budget, get something with more muscle. I'd look at the PHii x3's, x4's even the athlon ii x4's. You should choose according to what you think you need. The 955BE will run you $155ish, so that specific Mobo/RAM/CPU combo totals $340. Obviously, the more/less you spend on a CPU will influence how much your budget will be left for a decent HSF (which I would recommend getting) and a GPU. But let us know specifically what you game/plan on gaming, and what you might be doing down the road.
In short, my personal opinion is, don't half *** it, save the extra $50, and buy the Mobo/RAM combo, a 955BE w/ heatsink, and a GTX460 1GB. If your penny pinching, think hard about everything you might do with your computer.