I purchased a Sig 220 .45 for my dad last year. Very nice gun.
If you want a Sig 9mm, I would lean toward the 228. Frame size seem to fit the 9mm round nicely.
Have you shot an HK USP compact? Very nice gun in 9mm. Just be careful of which variant you are looking at. They make all sorts of models, some are DAO guns, other standard double action, some with safety, some without, etc.....
http://en.wikipedia.org/wiki/Heckler_&_Koch_USP