i like caversham too ... generally you can be guided by house prices, so if, for example you spot a 2 bedroomed house that is a bargain, its probably in a not-so-nice area.
Places to avoid (in MY opinion; i don't want to get in a row with people that live in these places) are
1)whitley
2)southcote
3)oxford road area
4)some parts of tilehurst
places where i, myself personally would consider buying a house
1)some parts of tilehurst (tilehurst village, for example)
2)some parts of calcot (not the bits on the north side of the bath road
3)most of the university area (but not by cemetary junction)
4)outlying villages ie burghfield, mortimer, sonning common, theale, pangbourne, purley
so so sorry if i've offended anyone at all
It might be a really good idea to come down and take a look around and see what feel you get for places! depending on how far out of town you have to go and how much money you have, there are lots of nice options further towards newbury, or further towards oxfordshire