Size definitely matters ("That's what she said!"). A lot of cases tend to have info (or you can Google it if they're popular) about inside clearance and all fans list their height somewhere--usually the Newegg page has it.
As far as coolers go though--there's a lot of crap out there and a lot of good stuff. A lot of fans have reviews. They really vary in quality (noise and cooling performance) so it's worth it to do some research. You can always start with the stock cooler and upgrade to an aftermarket one later though--so you shouldn't let the cooler hold up your build.
Who is she and why does she say these things?! heh
i looked at the frostytech website but i couldn't find anything really for socket 1155 cpu's but looking at the reviews for the one i hyperlinked it's actually pretty good.
I don't know if your case will need the extra fan--but I'm not familiar with the Antec 100 (Newegg only sells the 200, 300, 600, 900, & 1200). I'd consider Z68 for that motherboard. Z68 is worth it if it's the same price and not worth it (for gaming) if it costs more. Aside from some parts possibly being able to be found cheaper (GTX 560Ti, 8GB 1600CL9 DDR3), it's good to go. If you've already searched around for prices, then go ahead and pull the trigger.