CFM for guns?

I'm new to painting, but will be making my first gun purchase with in the next three months. I hope to be doing some kind of painting professionally, as I will be graduating Wyotech in March of 06'...

So far I've narrowed my choices down to these eight guns. But that's not my question, the CFM part is. Since I don't know where I'll be working at and what type of compressor they'd have - should I get the gun that has the least amount of cfm usage or is there a general (all around) cfm usage that I need to stay in between when buying a gun...?

My choices:
DeVilbiss GTI-620G / 15.5 cfm / Base/Clear
Finish Line III / 13.0 cfm / 1.8 tip Primer
DeVilbiss PRI-601G / 16.0 cfm / Primer
DeVilbiss SRI / 4.8 cfm / Touch up gun
Sharpe Finex F300 / 11.4 cfm / 1.8 tip Primer
Iwata LPH-400 / 9.5 cfm / 1.3 tip / Clear
Iwata LPH 300 / 7.1 cfm / 1.4 tip / BC/CC/Primer
Iwata LPH 50 / 1.8 cfm / Touch up

Thanks everyone...