I went there last year and it was amazing especially because Ferrari won the race. I was at various places during weekend. I watched qualifications at Parabolica, its great because when you get close to the fence cars are driving just about 3 meters from you.
What impressed me the most is when they come to the pits, full speed through Parabolica and then quickly downshifting to the first gear... that sound is awesome. I watched the race at Ascari which is also nice and you can get some nice pictures. Those of you who are close to the main straight be sure to check before the race where are the gates to the circuit because when the race is finished they'll open it up so you can go on track to see podium ceremony. You can also get some rubber from Pirelli's if you want.
If you want to buy some souvenirs I would recommend to not buy them at the main entrance(near main straight) because its much more expansive. Last year I was looking at F2008 scale model and it cost there 110€ and few hours later I found it for 50€ in the middle of the circuit.