I haven't checked prices but here are a couple examples of very high rated compacts in order of preference:
Casio EX-V8 (the size of a business card and under an inch thick)
Canon A550 (considered one of the cheapest good cameras)
Canon SD850 IS ( IS means Image Stabilization which means it can cancels effects of shaky hands)
Do you mean theS6500 versus the S5700? The bigger numbers normally come with higher pixel counts which is OK but you have higher weight swinging around your neck and there are more useless features as well. It really all depends on what you are planning to do with the camera. Holiday snaps and kid's parties? I'd just go for the S5700. Are you going to want to take serious pictures of your tank and maybe get creative? Go for the slightly higher quality available with the higher model number. I've heard those Fuji models referred to as "bridge" cameras because they are more versatile than the compacts but not quite like the DSLR's. You'll think I'm an elitist but I figure if you're going to get something that big and bulky why not just get the SLR? Then you don't have to worry about "upgrading" I'd just save up some more and get a Nikon D40 which is a cracking camera Â£290 at amazon (OK, Ok, I know, it's twice/thrice the price of the Fujis).
TDI-line, same analysis - the Sony compacts take good pictures, and if you only make 5x4 prints or just email the snaps to friends and family no worries, but what do you want to do with it ultimately? If it's for the wife, no problems - give that Casio a look though, she's more likely to want something cute, stylish and convenient I reckon. 8)
I'd want a camera that did a mix of stuff, but I'd mostly use it for the kids parties type thing. Although decent pictures of tanks/plants/fish would also be required. I'm not too concerned with pixel count as I can't see me blowing anything up to poster size.
I used to have a Minolta dynax 7000i which is now gathering dust at the bottom of the wardrobe. I liked it, but after a while I found it too bulky to take along to the beach or going to the funfair. Even on holiday, going out for an evening meal it's easy to take along a compact. My wife wouldn't appreciate me bringing along a bulky SLR for a meal out. I know the Fujis are bigger than a compact, but if they're small enough I could still persuade my wife to find room in her bag!
edit: Yes, cheers Clive, it's the 5700 I was thinking of.