1 question..what platform?
i also using quite small casing..
back exaust fan is 80mm.. so the clearance quite small..plus have to spare some for the 120mm fan attached to side panel..

i settled with xigmatek cobra.. rm90 robyncom.. average price around 105..
great HSF..but i guess compatible with AMD and 775 only i guess..
frenly reminder..the fan quite loud when run full speed.. low speed no prob.