You should of course get a Chessbase. I like Chessbase 10, but maby you should go for Chessbase 11 with the (as i see it) 2 new very useful options. I use it for preparetion, own game analyze, studying GM games, Chessbase magazine and building up my complete repertoire with all variations.
How to best use Chess Software
Thanks for your reply. If I get say Chessbase 11 is there the need to purchase every updated version, ie chessbase 12, 13 etc.? Also are there big differences between the versions of chessbase 11: premium, mega package, starter package. If I have chessbase then I don't need fritz?
I've also heard of good open source chess databases, does anyone use these?

it depends what u want to do in your chess. if you want to build a repertoire, chessbase 9 premium is probably the best buy for database management at 50 euro. there's no bugs in it that i know of on windows xp. its what i have and i see no reason to upgrade. SCID is the free version, its not quite as user friendly as chessbase, but the functionality is good and u can do more statistical analysis. chessbase light is free and works ok for dbs under 32000 games. Additionally chesspositiontrainer 4.0 beta should be coming out soon, which will be a good way to test your repertoire using a flash card type method. if u need games for database, there's twic, the pgnmentor, chessgames.com files, and the NIC base. For the best grandmaster games. The best computer chess games u can find out about via the rybka or talkchess forums for starters. to find all these things just google them.
for tactics, there's the chess.emrald site and of course the tactics trainer at chess.com and the chess mentor software and videos if u subscribe.
Regarding chess engines, my opinion is that all the parties are insane.
Upgrading your brain is good too, eating, sleeping, thinking, walking, all that good stuff. ‘tis the software that counts. Making sure the reality in your head equals the reality on the board
Yes I'm mainly after a program for repertorie building. What are the differences between the chessbase pagackages, like mega, starter, light etc. Is each new version of chessbase, chessbase 10, 11 etc. just mainly a database update?

You may want to browse around ChessCentral.com. They have several mini-articles describing the Chessbase database products and Chessbase 11 Starter, Mega and Premium, as well as Fritz 12 and Rybka. Steve Lopez is the resident software guru at ChessCentral. He is an expert in many software products, especially Chessbase. You can communicte with him through ChessCentral (he is the software support guy) or through the Chess Exchange forums, software section where he is a moderator and site administrator. I believe,he could answer virtually all your questions, if anyone can.
http://www.chesscentral.com/ChessBase_11_Starter_Package_p/chessbase-11-starter.htm
http://www.chessexchange.com/forum/viewtopic.php?f=7&t=4955
Good luck!
I'm rated about FIDE 2000 and want to improve my game to about 2300. I haven't played much over the last 4 years and would like to get back into serious chess. Due to my absence I haven't kept abreast of the developments in chess software. At the moment I'm using Fritz 11 and don't have any version of chessbase. Can anyone give me some advice on what software I should use and how best to use it?