FWIW - I have the 24-105 IS and love it. It's my carry around lens on a full sensor rig (and I have the 70-200 in all it's versions, 300mm 2.8, and f4, 24mm 1.4, and on and on...). I usually shoot landscapes though (and wildlife with the longer lenses). To me the IS is worth it and I like the little bit of extra zoom since if I can I only take the one lens on hikes and such.
I also have the 50mm 1.4 and 1.8 versions. You can get the 1.8 version (USA) for like $70 (it's plastic but image quality is awesome, do any search on it - sharp as a tack). 50mm is a great portrait lens and it'll give you the speed for your baby indoors or shallow DOF. I got the F1.4 version for the Northern lights (lots of motion) and because it's part of the sickness. Someone once did the math and the step up in light gain from F1.4 to F1.8 was only like 2/3 of a stop. Not a big gain compared to the price difference.