Below 140mm for Tower Heatinks....Noctua NH-U9B SE2 92mm SSO CPU Cooler
(125mm height)ARCTIC COOLING ACFZ13
(130mm height)XIGMATEK LOKI SD963 92mm
Or on horizontal....COOLER MASTER GeminII
(75mm with fan)Thermalright AXP-140 RT Low Profile Heatsink
(95mm with a fan on top, can fit standard memory below it, check my servemi build for pictures).Noctua NH-C14
(105mm with fan on bottom, 130mm with fan on top, with dual fans might not fit with memory below it, depending on how you install and your mobo layout)
Since you are thinking on a 2700.... and if you were to have room for it, i would go with NC-14, probably the best horizontal cooler around, and with the ultra low noise adapters should be decent... just its an expensive cooler. The GemninII and Thermalright AXP-140 are more HTPC low profile coolers... sort of speak, probably among the biggest for this purposes, the axp-140 can handle fine my Xeon E3 1230 with 700rpm fan (for the reference is similar to cpu between i5 2500K and i7 2600K, but doesnt OC), you can check my servemi build for prime95 tests, but if you plan on OCing.... idk might be better to go with the noctua, but depends if you build can fit it.