For basic cases I like the Antec 300 (lots of people dont like them, but I do). It has great air flow. 3 x 120mm fans and 1 x 140mm on top. It provides plenty of airflow. I owned the antec 902 and I like the case. I has great air flow. I ALWAYS mess with my computers and it is a pain to work in it. If you don't touch your pc much I would say go with this.
Lian Li are very nice cases! If you want to get a good upgrade get a lian li. Find one with good airflow.
If you buy an antec case, I would suggest buying one used. Preferably one with mods. I also suggest you give it a good paint job. Nothing like owning a case that you put some work into it. Antec cases can be found cheap here on OCN.
Sell that case you have on craiglist for 20-30 bucks!! 15 for a quick sale!