Hey Milvus,
I don't know if I'm the best one to give you advice as I'm a Newbie too, but since no one else is, I'll give it a crack. I have just gone through the process of buying gear with little experience so I know how daunting it can be. The only real advice I can give you is don't get too hung up on brands if your buying second hand as it probably limits your choices. Asking which brand on this forum is like asking Landcruiser or Patrol, both do the job but everyone is going to have their own opinion. I picked up a brand new board and harness and a second hand kite, all 2010 gear for just over $1700. Although the kite is second hand it is in perfect nick. I got it all on here through the buy and sell section. Pretty dam cheap entry to the sport I reckon. The thing is I wasn't concerned about colour or brands, I just followed some advice through this forum. I think any Newbie is going to find it hard to tell the difference between any of the late model Hybrids. My purchase has got me on the water and once I have some hours up (or years) I will be in a much better position to choose my second and third because I will hopefully be a lot better than I am right now an will be able to demo all that's on offer. As for kite sizes, sorry I really don't have a lot to offer there. I am 80kg and went for a 12meter and a 137 x 41 board. You have to remember that board size is just as important as kite size. I have a mate who is 95kg and he also has a 12meter kite but he has a couple of different boards for different wind strengths. What ever you do, just get some gear and get out there, it really does change your life. Hopefully someone with a bit more knowledge can give you some more advice but I hope my 2c helps.

^^ DM is right about the Catalyst. And 8 years down the track after many kites from other brands I fly the Catalyst now and would not change.

Another vote for Catalyst