Hybrid commuting - bike rack recommendation reqd

millsn

I'm toying with the idea of driving to the outskirts of Bedford and then getting on my bike to cross the town and get to work. Can anyone recommend a bike rack for this purpose? The thule ones look nice but seem pricey, I don't like the rear of car racks too much but could be convinced. What are the arguments for and against?
The rack would need to be toe rag proof so it didn't get nicked but the bike wouldn't stay on the car long in dodgy areas.
Anyone do this themselves?