You said gaming, so i'd say avoid the pressler, 4mb of l2 cache still doesn't make up for the higher latency in accessing memory [compared with an on die controller] if you are a gamer. If you must buy now, try and find an opteron 165 or 170, the better stepped ones on a dfi nf4 ultra d will run pretty much as fast as an FX 57 on air and they are dual core!
I would get the dfi nf4 ultra d as a mobo as it is still excellent, if you want a bit more get the dfi nf4 sli expert as it is quite simply the best pc motherboard in exisistence.
Grab 2gb of reasonable overclocking CAS2 PC3200 (some cheap end OCZ maybe), as everybody keeps saying PC5000 on an AMD system is expensive, hot and for the most part pointless, you may as well spend the extra $$$ on other things.
You can probably afford one of the recent seasonic psus, if not I recommend the enermax liberty series.
The X1800 XT overclocks like a complete beast, but the 7800GTX is faster at stock (ignore the 512MB GTX it's a waste), the 7800GT and X1800XL are both pretty solid though.
However I would suggest that you hold on till probably march when the next AMD socket should be out. 939 stuff is likely to become quite a bit cheaper, and the new socket supports DDR2 and probably there will be a new improved AMD chipset from via by then (it looks quite promising).