I bear the PC wealth guidelines in mind as a cap on the maximum amount of usable magic gear a PC should have at any particular level if the CR system is to work right & the classes be roughly balanced, but I use the NPC wealth table as the standard starting amount for PCs and roughly the minimum amount they should have to be balanced vs each other & the monsters. The main effect of the guidelines is that I run mostly published scenarios and I've noticed that published 3e scenarios usually have much less treasure than their 1e/2e equivalents, I even find myself increasing 3e treasure hoards which I never did in earlier editions.