1) Which brand of ram (in your opinion) is the best?
2) Is 512 MB enough? or is 1 GB worth it?
3) Is ECC really needed? (don't see much ram having this feature)
4) My MB could only support up to PC2100 DDR ram. I plan to upgrade my MB in the near future (dunno when, maybe when the next intel CPU comes out) so should I get the higher speed ones (PC2700 and up)? And if I do buy such would it still be compatiable in my P4B533?
Note about how I use my computer

1) I don't overclock but I do use aggressive timings.
2) I generally use programs like Photoshop and such. Also 3D games like Quake 3 and such.
3) The computer is on for a long period of time (average of 8+ hours/day).