Surprised no one has mentioned the GK MB200 head. Pair that with an 8 ohm cabinet and you'll have a pro-quality practice rig.
Another option is the Ampeg BA-112. It's a great sounding combo with the features you're looking for. I've had one of the older US models and every time I pull it out thinking I'll sell it I'm reminded how great it sounds so I keep it around. It's no slouch and definitely no toy.
If you'll be playing only through headphones, I'd suggest a Korg Pandora. Too much tweaking but works wonderfully for the job.
If you'll be playing through headphones most of the time but want the option of playing through a cab, I'd suggest the Ampeg Micro-VR. The Micro VR is unique in that they maintain the original signal of the aux in / mp3 to the headphones, so it sounds like you're plugged into the iPod directly. Most amps mix down the separate stereo channels to a mono signal (so it can play through the cab) and redistribute to stereo for the headphones. So on the Micro VR you hear the original recorded mix (say, lead guitar on left, rhythm on right, vocal pans etc) vs. hearing the same thing in both ears. Personally, I record at high bit rates and enjoy listening to music through headphones, so it's an important feature. If I didn't have the Pandora, which does this, I would have kept the Micro VR over the MB200. The MB200 just sounds so much better than the Ampeg as an amp (to me), plus I got a great deal on the GK (just under $200) and used a 20% coupon at MF for the GK Neo112-II (arriving tomorrow). But if I were mainly practicing through headphones, and had no other tool, I'd go with the Micro-VR. In fact, since I returned it Friday I've been wondering if I made the right call.
Keep in mind that my reference amp is a Mesa Walkabout Scout, which I've been using as my bedroom amp for a long while.
Sorry for the ramble. Hope it helped.