Vox Amphones

These were on sale on Amazon recently, about £55.  I went for the lead model, there are also a 'Twin' and 'AC30' model for guitar and also a 'Bass' model...well you can probably guess what they're for :-)
 
Really, surprisingly good.  Lots of crunch and bite on lower gain settings, think Black Sabbath guitar tone on higher, so I've been making loads of nasty bottom string bends with a big smile on my face.   The delay and reverb work perfectly well; I'd like to be able to dial a bit more in, but what's there is adequate.  Not really tried the chorus yet.  There's a 3.5mm jack for plugging e.g. an mp3 player for jammin' along. 
 
They're pretty good stand-alone closed-back headphones too, made by Audio-Technica.  In fact, if you bought a pair of bins for that money of the same quality, you'd be quite happy.
 
Note, they are loud.  Dial in a bit of gain and you really don't want to turn the volume control much past 2 (of 10).  Much higher than that and your brain is likely to shoot out of your nose.
 
The controls are quite small and next to impossible to tweak whilst the headphones are on your head.  Not a biggy though, it's not much hassle to pop them off, make the adjustments and pop them back on again (in fact, due to how loud they can go, it's probably for the best to tweak settings with them off your head).  They're a touch chunky due to having to hold 2x AA batteries on one side and the amp emulation circuitry on the other.
 
This (lead) model seems to play best with high output pups and works well with active ones.
 
For silent, hassle-free practice they really are ideal; sometimes I just want to plug and play without setting up pedals, amp, headphones etc. and these are perfect for doing just that.