I'd hardly call some of those companies start-ups. Take Blinkbox for example, that's backed by a FTSE 100.

On a more serious note, what do other devs feel about working at startups themselves (freelance + perm)? The only I nearly got involved in was folded within 6 months. I'd have potentially been in a very bad situation as a result had I gone through with it.

[edit] I'd do piece meal work. Throw in hours along side my regular job but going full time without a decent golden parachute would worry me.