I have a 4" .45 ACP and I love it.
While I don't like IWB, I sometimes have to go that route and I own several from
High Noon Holsters . They are excellent.
For normal carry I use a BlackHawk CQC Serpa paddle/belt holster. It's easy to adjust and comes with both paddle and belt attachments so it's very application flexible.
I have the x-project galco holster for my car, only because I can 'button' it onto my belt without much effort (moving my gun from 3:00 to 9:00 for cross-draw).