What motherboard is the Dell 8200 equipped with? If it´s a i850 variant, then it´s probably a solid computer... But if it´s the i845, then its memory system is probably outdated... Is it on SDRAM (yikes) or DDR?
Willamette cores are usually very slow beasties.. Northwood fare much better. I think that your switch from 2Ghz Willamette to 3.00Ghz Northwood with HT on, say, a Canterwood or even a Springdale mobo will produce interesting results...
But if you don´t have the money to do so, I think that upgrading your video card is already an excellent alternative, particularly if you use RDRAM. Your memory/mobo/CPU system is probably enough for what you want. Besides, if your current setup isn´t troubling you in any way (maybe you´ll want to upgrade your video card for a Doom-3 capable one when they come or something), I don´t really think an upgrade is needed...
That´s what I´m doing. I currently have a 1Ghz P3 which is doing fine for now (it´s got a GF4 Ti4200), but certainly won´t be enough for Doom3. So I´m not upgrading while there´s no good reason to do so. But come Doom 3, and I WILL WANT TO PLAY IT. So guess what? Upgrade.
You want to save money use 2.4c, 2.6c or 2.8c. If you have lots of money than wait for Prescott. Going with Prescott you need to buy Canterwood Mobo. The three chips can be OC. The 2.4c so far looks like the best bet for Ocing. I buying 2.4c next month. Then next June or so depending what Intel has for Prescott I'll upgrade my Cpu to Prescott.
Going for a P4 800FSB with Canterwood mainboard and GeForce FX5900 Ultra or Radeon 9800 Pro, would definitely yield a big performance increase, if you ask me. Whether or not it's an increase that's big enough to justify a purchase is of course a subjective opinion. It's also tough to say if you should wait for Prescott or not, judging from what that will be added with that CPU, I'd say it may be worth the wait. If you don't want to wait though, then firstly, I'd recommend a Pentium 4 2.8 GHz with 800 FSB (good price/performance ratio) and Canterwood mainboard, from MSI or Intel themselves.
To recommend a video card is a bit harder. The GeForce FX5900 Ultra is the fastest gaming card for the moment, however the Radeon 9800 Pro is a bit cheaper. If you are willing to spend more money for the 5900 Ultra, it will pay of in performance though.
So I guess my recommendation is to buy a R9800 Pro or FX5900 Ultra now and wait for Prescott.
My system: AMD Athlon XP 3000+ CPU / TwinMOS 1Gb DDR400 / Soltek 75FRN-RL /
Sapphire Radeon 9800 Pro / Antec True Power 550W / Maxtor 80Gb ATA-133 / Hercules GTXP SC /
Samsung DVD / Lite-On CDRW
actually the 256mb version of the 9800pro costs the same as the FX5900Ultra
also i think you just need to upgrade into a midrange card at the moment cause as we all know dell gives you underpowered powesupplies so it's less upgradable beside i think that anyone that has a CPU of 1.8 and lower for intel and anything below T-bird for AMD are the one that should be worrying about upgrade the rest i'd recommand waiting for the prescott or the Athlon 64s cause if they are high overpriced once they came out the mid range CPUs will also decrease in value therefore u'd get more choice and a better deal^^