I'm not running my teams right now, but some recent hardware issues have caused me to look at upgrading some parts and making some swaps, and I'm keeping my teams in the back of my mind.

Current box, I ran 4 toons to 60 several times with this:

ASUS M2N-SLI Deluxe Motherboard
BFG GeForce 9800 GT OC 512 Card
AMD Athlon 64 X2 5600+ Windsor 2.8GHz S Dual-Core Processor Crucial 4
GB (2 x 2GB) DDR2 800 (PC2 6400) Dual Channel
XP Pro
2 160 GB 7200 RPM HD (both IDE drives, Seagates)
Running on a 22" widescreen Viewsonic monitor

Have been having some freezing issues, the screen would just lock, no artifacting, no apparent heat issues, I've blown the case out several times. I thought it might be a memory thing, as it seemed the longer I had gone since a reboot the more likely the freeze was, it also showed up the more windows I had open. I guessed I had a bad chip on one stick that only got accessed when I had a lot open or hadn't rebooted for a while. I planned to test it, but hadn't gotten it done, I generally started rebooting just before raiding time and it worked fine.

Then last week one of my hard drives flat disappears, it's not being recognized at all, ruined a night of raiding while I updated one of my installs on the other HD. Hmm I think, maybe that HD was dying. Then the system freezes again. Then 2 days after the "missing" missing hard drive is recognized normally and I can launch wow from my solo play folder.

Friend of mine has the same mobo, and we're thinking that's a likely culprit, so I'm starting my shopping, asking for recommendations or experiences with how much of a boost to expect from various upgrades.

Upgrades I'm considering, in order of importance, using some of anandtech's guides for input (he did a new one today http://www.anandtech.com/guides/showdoc.aspx?i=3563&p=2 ):
New mobo (ASRock A780GMH/128M maybe?)
Hard Drive (at a minimum get away from IDE, but 1 SATA, dual SATA, SSD?)
New processor (Probably Phenom II quad core, the new 45nm units)

I'm looking at AMD because of familiarity and longtime comfort with them, and I like that the newest CPUs are compatible with DDR2 and DDR3 so I can delay a memory update.
I'm not planning on going to Vista on this box, planning on making the jump to 64 bit and 8+ GB memory on the newer OS when it gets a little more mature
Not planning a video card upgrade at the moment, though I have set a budget aside if I need to update my PSU.

I don't overclock, I don't need massive HDs, the two 160s were half full, though I have multiple wow folders on both.

This is too long for a simple request for input on mobo/processor/HD upgrades, sorry.

Budget 2-300 bucks, likely newegg.