I bought an Aston Stealth a few months ago and I've been pretty impressed with it. It has 4 'voicing' options, two of which are horrible, but the other two are both very workable.
But I primarily recommend it here because it seems to have very good off-axis rejection.
Not cheap, but probably a good investment. In the 'good investment' category, have a think about a Beyer M201 as well.
But actual cheap dynamics, my preference is for the AKG D5. It's the nicest stage dynamic I've heard under £100. And being a stage dynamic it expects to be worked very close which will help reduce the effect of your room and background noise.
Or just get a '57 and know that you've got something that will be eternally useful.
I’ve got a 57 and a 201, the 57 gets used the most, it’s a useful all rounder.