what are your system specs? specifically, case, mobo, pcie cards
depending on how small your htpc is, your choices may be fairly limited... for example, with a mini-itx setup in a Sugo-06, you're limited to a heatsink height of ~80mm (with fan) because the psu is above the processor. Also, on a mini-itx h55 board, you're typically limited to a ~20mm extension from the LGA1156 mounting holes (at least in the direction towards the expansion slot, if you use a pcie card).
For my htpc, I am waiting for a couple places to get the Prolimatech Samuel 17 as it seems like a decent performer that fits into very small places.