G'day Luke,
There is so much to see for such a tiny Island as i discovered in my 10 day trip and i missed out on some places so it all depends on how long you will have there and what your budget is at the moment there are some great short breaks using Tas vacations from a short 5 days to 14 days including car hire and accommodation, You can also go it alone and just use their site to gather information for your self, bear in mind it is also the school holidays then and prices will be up.
The west coast is rugged and very mountainous and the north is beautiful and scenic the interior is flat and full of history the east coast is little village's full of seafood and cafe's.
here is Tas vacations web site
http://www.youtube.com/watch?v=LCk9yvEpvtc...mp;feature=fvwp I found it to be very useful when booking, also there is a Tasmanian starter kit it lets u see whats around here is the link and if u have any questions i am sure the local expert there Will would be more then happy to answer any questions you have.
http://www.travelpod.com/forums/index.php?showtopic=40881cheers Stewart