Well, what error are you getting with that Gainward card? Might be easy to fix by just changing the driver.
The fastest motherboards on the Pentium 4 side are those based on the 875, or Canterwood chipset. Springdale (i865) should be released soon and is apparently just as fast as Canterwood and much cheaper. I really wouldn’t get anything but an Intel chipset. Both these chipsets support dual-channel PC3200 DDR (400MHz) and the new 800MHz FSB P4’s. This would mean buying 2 sticks of RAM of equal size, speed, and (preferrably) brand.
On the AMD front, the king is the nForce 2, although the Via KT400A puts up a pretty good fight. The nF2 is dual-channel DDR, but it’s not required for the system to work. You do want to have dual-channel DDR used if you want to make the most out of the chipset. Featurewise, you’ve got USB 2.0, Firewire (IEEE1394), 5.1-channel sound, and dual-NICs (optional). And the sound is one of the best solutions available.
For the KT400A, it’s a single channel DDR setup. While it’s not able to top the nF2, it does come pretty close.
I can’t really tell you what’s the best motherboard, but I can recommend certain brands.
MSI, AOpen, and Abit are some of the less expensive brands. MSI tends to offer anywhere from 2-4 variations of the same motherboard, so you can get one with just the features you want. AOpen usually isn’t too exciting, but they’ve got solid, stable motherboards. Abit used to not be one of my favorites, but they’ve cleaned up their act. If you’d like to do overclocking, Abit would be your best bet.
SuperMicro and Tyan are the best you can buy, but typically don’t include a lot of stuff. Additionally, SuperMicro currently only does Intel-based products (this should change with the AMD Megatron…err, Opteron). Both are known for server products, and thus overclocking isn’t going to be there. However, if you want something that’s nearly unkillable, these are the way to go.
Asus and Gigabyte are probably the most expensive of what you’ll be looking at. Gigabyte is like MSI in offering multiple variations of the same motherboard. Asus is a company that’s good, but you do pay extra for the name.
I can’t really speak on: DFI, Soltek, Albatron (headed by former Gigabyte official), Shuttle, or Soyo.
I’d keep far away from Epox, FIC and ECS. ECS is cheap, but for anything beyond a basic system for basic tasks, stay away. Epox quality control isn’t all that impressive…and don’t even ask about FIC—simply horrible support and even worse products.
CPU: The 3GHz P4’s are the king right now. The HyperThreading on them acts like an extra CPU (well, more like 1/3 extra of a CPU). For AMD, the Athlon XP 3000+ is a wee bit expensive price/performance wise, so look at something a little slower like the 2500+ or 2700+. These are based on the latest Barton core and use a 333MHz FSB unlike the those based on the older Thorougbred and Palamino cores. They also have a sweet 512kB L2 cache as opposed to a 256kB L2 cache on the T-breds and Palamino cores.
Memory: If you want the best you can get, buy Corsair. Otherwise Samsung and Crucial. Don’t get anything slower than PC2700 (333MHz). PC3200 (400MHz) is nice, but not necessary usually. If you plan on overclocking or getting the 800MHz FSB P4’s with a Canterwood/Springdale setup, that’d be a good thing to go for.
HDD. Western Digital has some 36GB SATA drives that spin at 10,000RPM and come with an 8MB cache. This is the fastest thing you can buy outside of SCSI. WD doesn’t have a SCSI division anymore, so they’re not endangering that market. Maxtor is also good. IBM has had problems, and after having 2 out of 3 IBM drives die on me (2 were of the 60GXP line), I find it hard to recommend them.
Graphix wise, look at the ATi Radeon 9800Pro for the top performance. It’s a bit faster than the 9700Pro. If you want something a little cheaper, but with at least the power of a GF4 Ti4600, get a Radeon 9500 Pro or 9600 Pro. The GeForce FX isn’t something I’d even consider based on all the reviews I’ve seen.