I definitely 2nd the little mixer option. All of my little mixers have preamps on each channel. If you also have FX on the mixer that will probably be enough to get you a sound that you like, especially if you're doin jazz tunes and clean tones.

Otherwise it might help to have something to plug into, like I use a line 6 pod sometimes when I play through headphones. Things like that allow you to sculpt a realistic guitar sound. You can either run that through a mixer into the CPU, or some, like the pod, have a USB out right into the computer.

Just a couple of ideas, I always gig plugged in, but I can't remember the last time I practiced through an amp at home! Always unplugged or headphones for me.