What's the best way to do the trip over in 2012? Cost, advice, etc ...

first thing to remember the game is at a different stadium in Montpellier this year,a couple of miles from last years venue - probably a taxi or bus ride from te centre

Montpellier is a great city to live, there is so many bars and restaurants, hotels, not to far from the stadium. But the best is the tramway, and take it to move fast, you will go easily to the stadium (line 1).Also, you can take the bus, take the line 15, 25 or 34.

First thing to do is ignore the "official" packages.
My hotel in Perpignan (next to the castle thingy) is £400 for the whole week
£470 for 3 nights?!

Get on the tram. Tram 1 (blue line) terminates at "Mosson" (which is the stadium) whilst the new Tram 3 (green line), which is a new line since we went last year, also stops at "Mosson". Easiest way to travel in from within the city.