If you buy good parts then when you decide to buy a new frame, and you will, you just Change over the parts and you're done.....
Never have to upgrade with good parts.
If you want to spend 50 bucks more i know of someone here in Dallas (bike mech) selling a sugnio 75 with a sugino zen racing 48T.....just example.
If you look around you will find GREAT parts for very little.
Good cranksets.
Sugino messenger, 75
Campy record (super expensive but pretty)
Origin 8 (very good bang for your buck)
Socks