Hello all experienced circuit designers:

Given the plethora of suitable:

 A) bybass cap values and 
 B) SMT physical sizes (not to mention various temp. stability options) 

listed in the Digikey catalog - 

Has anyone found/experimented with the optimum size capacitance 
value and/or physical size for use in/around a microprocessor?

I've got a 100 pin QFP device that I'm laying out and would like
to score on (or slightly near the mark) the first time around ...

I've got access to the under side of the board - and that's where
I had intended on placing the SMD bypass caps.

The first few boards will be hand-built prototypes (of course!) - so
am I better off with the larger size (1210 etc) SMD caps?

This is my first real exposure into the world of SMD - having done more
RF projects (most of those devices are 'Surface Mount' in practice!) in 
the past than digital/micro circuits using conventional TH or wire wrap
technology. 

Jim P