Hi Aaron,
All of the EF lenses will work with your 10D. The EF S lenses won't work as they are specifically for the 300D and the newer 20D.
Sigma,Tamron and a few others are all makers of lens' and as for the diference in each of them, well I guess thats as subjective as anything
Someone with more experience in lenses will come along to advise further
A good starting point maybe the PBASE website which has photo galleries indexed by lens used as well as camera bodies. Or you can search Google with the lens you are interested, like the 28-399mm
