If you are open to something a little different, look into the Fender B-DEC 30.
It's a small, 30 watt/10" speaker amp that has a number of great features. Not only can you can plug headphones in, but there is also an input for an iPod or other device. Best of all, there's a built in "bass teacher".
If I remember right, the built-in effects include 60 or 70 different jams and teaching loops that you can customize (tempo and key) to make you a better player. A built-in tuner and metronome will also save you on extra purchases. For fun, you can also choose from a number of effects like chorus, phase and flange, as well as a half dozen or so amp sounds.
Here's some YouTube:
I have one and I'm very happy with it.