I feel like you're thinking too far ahead, chances are you'll live in Lenton whether you like it or not because one person in your group really passionately wants to live there but, every area has it's pro's and cons so i'll try and spell them out for you.
Lenton:
+Good transport links to the city centre 34,35,36 buses and a fiver in a taxi.
+It's the student Mecca for Nottingham, chances are it's where your friends will be living.
-You end up paying for the reputation rather than the quality of housing
-You'll get the bus every day if you live any further than Kimbolton Avenue
Beeston:
+Plenty of shops around, massive Tesco and a decent sainsbury's aswell
+Houses are really cheap and relatively spacious
-You live in Beeston
-It's really far away from anything.
Dunkirk:
+Super close to the university, especially if you're doing engineering/science
+Still has a fairly high student population and a few decent pubs.
-No shops at all
-Transport links anywhere suck compared to the rest of Nottingham.
Also worth checking out Radford (Lenton's chavvy cousin), Wollaton and even West Bridgeford (if there's something wrong with you) .