<i>I Have a wide range of music tastes so don't just want a beep maker, don't need anything too professional, as i mainly intend just to play around to start with, but the other half is in a band so potential to guest on some tracks?
Can read music so not a complete beginner. </i>
Makes a change 😉 These days it's mostly 'yoofs' who fancy themselves as DJ producers and can't actually 'play' for love nor money 🙂
More info would still be useful though, you say you read, have you any keyboard skills? If yes you might want to think about something with a weighted touch sensitive full-size keyboard.
Your other halfs band, do they use any software / a Mac? What kind of music, will you be playing live or putting down tracks on the Mac etc.?
Are you interested in programming your own sounds? If so I'd ditto grums comment about getting something with knobs and sliders on.
Finally, what's your budget?