RC-690 $55 Maybe not the best - but its a great case and an even better value for your case $$$ A lot of us are kicking ourselves that we didnt order the RC-690 back when it was $30 after rebate. RC-690 Review @ HardwareLogic
RC-690 is a great case.
Other good options for 40-50$ is the CM Centurion 5 and 534... by adding 1-2 fans to either of those you can get great cooling performance.
I have a 534 with E2160 in it OC'd to 3.0 running cool and stable. Just had to add front intake & side exhaust. (2 x $3 or $4 80mm fans)