Security can be an illusion though. For instance, onename (I think) dropped namecoin because it had a high hashrate that was completely dominated by a single pool, f2pool i think. Same deal for huntercoin, which uses both sha and scrypt, but f2pool owns 99% of the hash on both algos I think (tho they've announced they're going to stop mining huntercoin soon).

I think myriadcoin has a nice approach of using five algos, sha and scrypt being merge mined, and the three GPU/CPU algos not. That way a single monster ASIC pool can't own the coin least. Unitus also has an interesting approach of using five algos all GPU/CPU and all merge mined.

Tl;dr - hashrate != security