Any recommendations for a place to impress someone, luxury but without breaking the bank?

I can personally recommend the Hotel Cacciani in Frascati – a 30 min train ride out of Rome. You can see Rome from the balcony (the '40s' rooms are the best) and it is a beautiful small town on a hillside – lovely to wander around:

cacciani website

Ripa Hotel, Via Degli Orti Di Trastevere 1. Walking distance to centre of Rome but not trendy area so reasonable price. Style is cool semi minimalist. Have stayed there 3 times, last about 3 years ago

Cap'n – that looks nice!! I like Trastavere, as well.

TooTall – I am going with someone who has not been to Rome before so looking for something a bit more central. Nice idea, though !!

We stayed here 47 Hotel – Rome and it was lovely, nice huge walk in shower (big enough for two), it was really quiet inside, nice and central round the corner from the Forum. Would definately recommend it.