Ive always liked the E30 M3 but it would be more of a vanity thing for me, mainly because of its rarity and appeal, Ive never driven one so I couldn't really say too much but I'd imagine the performance wouldn't blow you away... maybe it makes up for it in driving enjoyment but for going out for a hard blast in something with a bit of oomph it would have to be the E46...

All that said if the two sets of keys were left in front of me I'd probably have the E30.