Hi Ian,
welcome
that question has a lot of variables that you need to answer.
a MIDI controller doesn't have any sounds itself, you have to use softsynths in MC to get it to make sounds.
a keyboard has sounds that you can record EITHER the MIDI output or the AUDIO output to record the actual sounds. usually you don't want to do that unless you're recording a keyboard which sounds really good (one of the higher end keyboards such as Nord, Yamaha Motif, Roland Fantom, Hammond, etc)
All modern keyboards will do BOTH sounds AND MIDI.
All controllers will only do MIDI.
most modern MIDI from keyboards are done through USB. If your soundcard doesn't have MIDI ports then you definitely want to check to make sure the keyboard/controller you buy uses USB for MIDI I/O.
prices range from $50 to thousands (i.e. Yamaha Motif XF8 = ~$3700 street price).
the feel of the keyboard is another thing you need to consider. if you're a pianist, you really want a controller/keyboard which has 88 weighted keys. And none of the brands feel the same. Personally I've tried a lot of weighted keyboards and my favorite feel is the CASIO Privia line. Good value for the money, too. ($500 to $1000 new).
if you are an organ player, you want a keyboard with "waterfall" keys. if you're not an organ player, you won't know what that is.
. a budget organ with really good sounds and is very lightweight is the Hammond SK1 ($1900 new).
If you want the synth feel, there are a lot of options. My preference is the Yamaha line for this. they put out some stuff which is geared more toward people who like to build up songs on the keyboard itself (ES series which are $250 and up), the PSR systems which are "personal keyboards" and geared toward beginners (starting around $99 and up) and the MX series which are low cost but higher end sounds than the ES systems ($500-$700) and the MOX series (or the MO series for used, older models) which are really powerful and great sounding synths without as much sequencer functionality ($1200 to $1700 for new) and the Motif series which are $2500 to $3700 and they are full blown sequencers.
I have not gone over MIDI controllers themselves. I currently own 1 MIDI controller I use for "quick inputs" and that's an M-Audio Oxygen. It's also good for taking on trips since it will fit in a suitcase and connect to my ipad. but the keys are not full size keys, they're actually even smaller than synth keys and they're slick and sometimes my fingers slip off of them.
what kind of soundcard are you using with MC? are you trying to use the onboard soundcard? If so, I recommend getting a recording soundcard instead. we can help you with selection of that as well. But it's more important than the keyboard itself, IMO.