I partitioned mine 60/20. Be aware you need to keep a free space on the partition, in my opinion keep 10GB free always as this is needed for TRIM and other optimisation.
Why I took 60/20?
On de 60 there is my OS and programs like Office 2010 etc. I also installed iRacing on this partition as I had some space left, loading goes sooo damn fast. In about 3 seconds I am into iRacing.
The other 20 I use for my profile, I moved the users folder to that partition. Many games like Race on etc write data in the Documents folder which is in your profile. With my setup I will never have issues when replay files or other big files are saved during a race. Also when you boot your pc your profile gets loaded, this goes faster when it is on an SSD. It is good to split the users folder apart from the OS, When i need to re image my system I will never lose my Userdata, as this is on my second partition.
Also be aware you need to disable a few services like Superfetch and indexing. There are more, just google on "ssd windows 7 services disable", you will find a lot of tips then.
Some say you can disable the page file too, I think you should set it too 3200, a solid value as some program really need it.
Also flash your drive to the latest firmware, this week Intel released new firmware, it can be found on the Intel website.