It's definitely worth investing in a good mouse as it will improve your workflow no end. Logitech is a very good brand to go for as mentioned above. Bluetooth is handy as it rules out the need for a usb wireless connector, but logitech make a range of wireless mice that come with their usb 'nano reciever' which is small enough to leave in all the time, even when the laptop is in a case.
I use the logitech anywhere mouse. It's a bit pricey (£40) but is definitely worth it. It uses the nano reciever and has laser tracking that will work on any surface so you can use it anywhere you want.
It also has a really usefull scrolling wheel that you can set to 'free spin' which is really handy for fast scrolling around a large project with many tracks in your DAW.
If that is a bit too steep then check out other Logitech mice, but generally I would say that you definitely want to go wireless or bluetooth and don't go for anything really cheap as the tracking on the cheap ones is often pretty rubbish.
http://www.logitech.com/en-us/mice-poin ... vices/6536