Needed: Computer Geeky Advice

[eapa]

I'm lucky enough to have a bit of extra cash this December, thanks to a winter/holiday bonus from The Job. While I know the wisest thing to do would be to throw the entire thing at my debt and/or savings, I really want to do the thing I've been putting off for almost two years now, which is to upgrade my computer. The last time I upgraded was when I built this machine, back in 2004.

I've tracked down the specs on my current motherboard, a Shuttle AN35N-Ultra 462(A) NVIDIA nForce2 Ultra 400 ATX AMD Motherboard (thanks, Newegg, for keeping my ancient buying history: http://www.newegg.com/Product/Product.aspx?Item=N82E16813150045). The other current specs on my computer are as follows:

AMD Athlon XP 2500+ Barton 1.833GHz Socket A Processor Model AXDA2500BOX
512MB RAM
POWERCOLOR R96-C3G Radeon 9600PRO 128MB 128-bit DDR AGP 4X/8X Video Card
32x/10x/40x Sony CD-RW (not sure if the burning function works anymore, since I haven't used it since 2004)
unknown speed DVD-ROM (no write capability)
40GB Hard Drive, currently partitioned into 5 sub-drives -- my ex did this, I personally have no idea how to do it
Sharp 17" Flat Panel monitor
Windows XP - a used copy I bought when I built this computer, so I don't know how many hoops I'd have to jump through if I had to do a reinstall (I haven't reformatted, or even had to reformat, in the entire time I've had this PC).

It's been a long time since I was hardware-geeky, so a lot of the numbers and acronyms are gibberish to me. However, looking over the specs of my motherboard, I've figured this much out:

• I can upgrade my RAM to 3GB; all I really feel I need is 2GB. But I don't know if it's worth it/feasible with a 1.833GHz processor. Also, the memory has to be DDR 400/PC3200 format
  
• I don't think I can upgrade my processor, unfortunately, since it doesn't look like my motherboard supports any of the ones out there that are currently commercially available.
  
• I can't buy any drives that connect with a SATA port, so I'm limited to IDE, but I don't know if this is a distinct disadvantage.

I'd like as much as possible not to have to buy a new motherboard, since that's essentially involving a complete and utter rebuild of my system. Which I can probably afford, since I can scavenge some of the hardware from my current computer and one that work gave me when we did a company-wide upgrade. Also, the most intensive stuff I do on my home computer is probably using Photoshop CS, watching DVDs (my computer is also the closest thing I have to a TV), and occasionally playing some sort of PC game like Age of Mythology or Dungeon Siege or something. Maybe if I had more power, I'd play more stuff. But whatever. I'm not a gamer at the moment.

So what I need to know, o computer geeky friends, is:

1. Is it worth keeping my current motherboard, which also means my current processor, and just upgrading my memory, hard drive, and disc drives? I'm currently looking at buying 2GB of memory from Crucial, an HP DVD-RW and possibly some kind of ginormous HD to be my primary slave drive, keeping my current 40GB one as the master, since that's where the OS is installed. Oh, and a new wireless card, since my current one is shot to hell and I'm having to string an ethernet cable across my apartment from my router.
   
2. If I stick with my current motherboard/processor, can I upgrade to 2GB of RAM? Is it worth it, or should I stick with only 1GB?
   
3. Should I upgrade my video card? I know nothing about the specs on those at all, so I have no idea what would be the best card for my needs/budget. Also remember that I don't have a TV, so my computer is also my only form of video entertainment at the moment.
   
4. Should I just bite the bullet and buy a fancy new motherboard? If so, what do you recommend that's not too pricey but still has high reviews; something that will still be upgradeable five years from now would be best, if that even exists. I'll still need to buy the new DVD-RW drive, memory, etc., so this is the more expensive option, though also the more fun.
   
5. Should I really bite the bullet, and just buy a new system from Dell, since I get a discount through my company? That would be easiest, but least fun. Might end up being the same cost, or a little more expensive, than the above option.
   
6. BTW, I have just the one monitor for now. But adding a second is really, really tempting, since I like to watch movies and IntarWeb at the same time. Should I go for it?

I haven't really set a budget for this project yet, but I'll probably be willing to spend up to $500 or so. Depends on what kind of hardware I end up buying.

Thanks in advance to anyone who got this far and offers advice in the comments! I look forward to your geeky input.

PS: No, I will never ever buy a Mac. So don't even think about suggesting it. ;)