My motor isn't overly rapid (~320hp / 1532kg), but it still puts a grin on my face when I get the hammer down and it's certainly fast enough to get me into trouble. I already feel like I have more than enough power to have fun on the road (no way I can claim to have driven it anywhere near flat out when going for a b road blast and can still reach speeds that are plenty high enough for me), so I'm not particularly desperate to go for anything faster (although that doesn't necessarily mean it will never happen). I mean, it might make me chuckle when wringing it out in a straight line when the opportunity arises, but that's not really worthwhile IMO.
I do still think about getting into bikes at some point, but again I doubt I'd be going for anything super rapid (certainly not to start with!).
Regarding the BHP / torque conversation, BHP at the wheels is the only thing that really matters, either when talking about acceleration or top speed. Of course the shape of the torque curve changes the driving characteristics and feel of a motor, but the acceleration at any given RPM will be a product of the BHP and the weight and aero drag.