Theres absolutely nothing wrong with runing 4 sticks, I am running 4 sticks @ DDR510 2,2,2,6 2T timings, the difference between 1T and 2T is negligable in real life and bench marks except sisoft sandra.
What you need is a decent processor as its the memory controller that dictates how well your memory performs. I run 1:1 255 and have yet to experience issues in the 8 months I have run 4 slots full.
DFi boards do well with 4 sticks but the inexperienced can kill board, processor and memeory if they get too happy with settings. 2x 1GB is is unoticably faster than my 4x 512MB and thats only because the 2x1 is clocked 30+Mhz higher.