Piano , guitar , or computer

[harryupbabble]

you say you are overweight and love to sing
you have two things in common with pavarotti
a great italian opera singer
in case nobody else knows

so, hang in there?

[plastik koffins]

Both instruments got their pros and cons if you want technical answer.

Piano pros:
Can play orchestral size stuffs
A keyboard is always used for midi

cons:
Changes way too much your way of thinking if you practice in classical music
More expensive than a guitar
Not mobile

Guitar pros:
Sounds cool
Mobile
Could always record audio if you go into electric guitars

cons:
Limited in my opinion, not musically, but needs to be in a band if you want to feel the full harmonics potential of a song (excluding Neofolk style)

Hope it gives you some ideas.

[Twyn]

If you're mostly into singing and that's the focus, I feel like guitar might be the best option simply because of how portable and ubiquitous it is. Easy to always have one on hand to whip out and play something to sing along to