Check here for some good fizz guides. Solomid.net is a great place for guides ^^
Oh, and @Fivah: Do not build wits end on singed. He doesn't autoattack, and that means that the attack speed and the magic damage applied on hit is wasted. For MR, get a force of Nature. And get your E at level 1, then max your q. That's where your damage comes from. Rush a catalyst, then decide on whether to build a Rod of Ages (if you're doing well) or start a force of nature/banshees veil/some armour if you're not doing so well. And don't get boots of speed, they aren't as good as other boots. I normally go for merc treads.
For garren, start boots and /doran's shield then get one or two doran's blades, then start a fratmas/atmogs or something. An infinity edge doesn't hurt either. Garen is quite a decent tank without going full tank. And again, boots of speed? not a good idea.
EDIT: Also a brutaliser is pretty strong on Garren early game as well.
If you follow any of those guides except for the AP one I have worries for you. I don't even agree with all of the ap build, AS on fizz is dumb, i dont know why anybody does it. All the runes are completely off
you should get mpen marks, flat armor seals, ap/lvl glyphs and potency quints.
I can kind of understand the on hit effect fizz but still wouldn't build it
ive decided i want the new person instead of rumble or kennen the under water awesome looking reminding me of fizz person
Lessons learnt: Never chase a singed, a teemo nor a shaco. Anyone else missing?