Alright, with this year's Christmas money having come in, I'm looking at my options for upgrading my computer. But, honestly, I have no idea what's good, let alone what is a good price/performance compromise! So, I'm hoping for a little input.
Right now, I am running on a GeForce3, an Athlon T-bird 1.4GHz CPU on an MSI K7Master mobo, and 512MB DDR RAM.
Unfortunately, I don't have enough to get a new mobo, CPU, AND GPU. So, the first question is, do I get a new CPU/mobo or do I get a new GPU first? It will likely be at least 6 months to a year before I can get which ever part I don't get now. One other thing to keep in mind is that the AGP slot on my current mobo is 4x, so it seems to me getting a new GPU now instead of a new CPU/mobo would be the less effective route.
Note: I'm speaking in terms of gaming and other video intensive things, such as watching hi-res HDTV video files (the 700MB/hour ones). When it comes to the other things I do on my computer - browsing the internet, writing papers when I'm not procrastinating, etc, my current setup is obviously decent enough

Let's put it this way: I'd like to be able to play Doom 3 and Elder Scrolls: Oblivion with reasonable graphics settings after my upgrade and be able to play them with high graphics settings after completing the second phase (whichever part that may be).
So, do I go for a CPU/mobo upgrade first or a GPU upgrade first?
Second, if I should go for a CPU/mobo upgrade first, what are your recommendations? I know that I want an AMD processor. What I don't know is if I want to go 64-bit or not, nor do I know what is really considered a reasonable price/performance compromise these days.
A few things to note: I would like any part I get to be able to last 3+ years with livable performance. I'm a patient person, and I've lived with my 1.4GHz and GeForce2/3 (made the switch to 3 last year for free) machine for about 4 years now. The performance is only recently starting to bother me as it is only recently that most new games are simply not playable on it. Another thing to keep in mind regarding the mobo is that I have no interest in SLI. By the time I'm capable of utilizing any SLI capabilities, I'll need a new mobo and CPU anyway. PCI-e is not particularly important to me either. If I can choose between two comparable motherboards, only one has PCI-e and the other doesn't (and is cheaper), I'd go for the cheaper one. Since I plan on utilizing the parts I get in this upgrade for 3+ years, I can get whatever my next GPU will be in AGP and by the time I get one after that, I'll likely need a new mobo and CPU again anyway.
So, what's the word on the mobo market? What's a good balance between price and performance?
Hope that's enough info to get some helpful responses...if you need any more, just ask, and I appreciate the help
EDIT: Oh, and I have no interest in overclocking.