i'm going to be 30 next Saturday and I fancy taking up a new musical instrument (I already play the guitar and have a bit of knowledge of music theory from playing the flute as a boy).

have you got any advice for me regarding this? do you think I'll need lessons or can i teach myself? are there any good "learning to play piano" books that are aimed at adults? (all the ones I've seen seem to be aimed at kids).

also - i'm thinking of getting a keyboard rather than a piano for storage and transportation reasons, but i want to get a keyboard that has weighted keys and is portable. I'd like it to sound as much like a piano as possible but if it has a few other decent sounds (a nice string/synth sound or a rhodes sound that'd be great). Any recommendations? And how much should I realistically be looking to spend?

Thanks everyone.