Well I've been here for 18 years, so I'm either bias or more than qualified to answer this question :P
The area around the Universities and the city centre is pretty nice. Around the University is very nice actually. Not too crowded (compared to when I've been say London or Birmingham) and the Highcross has a lot of choice there, compared to when it was The Shires. Lot of different ethnic groups, and at Clock Tower every Saturday there's always some people appealing for money or singing their religious songs.
I did get called a "f***ing cream cracker" by a black dude once when I was waiting outside William Hill lol!
The further away it does get a little less maintained but I'd see no reason why you'd ever venture that far, there are no clubs or shopping facilities or anything.