Ooooh let's see...
1. Psycho Cat - I was 4 or 5, and we were visiting one of my mom's friends in Michigan. Their cat was in the backyard, maybe 50 feet away, saw me... then ran across the yard and attacked me. I had bites on my face and scratches on my neck and arms... needless to say, that cat was euthanized.
2. Golden Retriever - I was about 15, and was working at a vet clinic at the time, and a *very* aggressive Golden came for boarding. We had to use a catchpole to get her from her cage to a kennel run, and one day she slipped through the kenel run door and went on a rampage. One other employee besides me was bitten.
3. Labrador Retriever - I was 18, working in a grooming salon. I think the lab was more dumb than aggressive, but he didn't like me clipping his nails allt he same. That one nailed me on the shoulder, but luckily he didn't break skin.
4. Maltese - my *worst* dog bite. I was 20, working at a different salon. One of the groomers REALLY didn't like me, but I was just a bather at the time and had to follow orders from the groomers. This particular groomer told me to bathe a Maltese - no other instructions or warnings. I go to get the Maltese out of his cage, and the little bugger latched onto my hand. I ended up needing eight stitches on two fingers. Later on, I found out that the Maltese was cage aggressive, and would bite anyone *except* his groomer. Gotta love cruel people...
Edited to add: I remember an "almost bite" from an Australian Shepherd. I was maybe 7 or 8, and my dad and I were walking to the store. We passed a house where a loose Aussie ran at us, barking and snarling. He leapt at me, but my dar kicked the bugger in the face and the dog ran back to its porch. The crazy thing is, the dog's owner was on a chair on the porch, and yelled at MY DAD for kicking her dog. My dad said something like, "Ma'am, if I hadn't kicked your dog, he would have bitten my daughter... and then you'd have a lot more to be upset about!"