I have a Dyson DC17 and it does an amazing job of dealing with multiple pets, as long as you are good about vacuuming every 1-3 weeks. It helps if you make the effort to empty out the bin and wipe the cyclone holes down with a paper towel after every room to keep the air power strong. If you have long-haired pets, you may need to open and clean out the bottom part, where there's a soft rubber belt with teeth that hooks around one of the turning mechanisms. Scissor tweezers are really good for this. I also recommend washing out the filter periodically, even if it doesn't look dirty and the water is coming out clear.
The DC17 is really bad with dealing with long hair, though. If you have a significant other with long hair, you're going to have to disassemble the vacuum after each full cleaning to cut all the hair out with scissors from the rolling mechanism at the bottom.
The construction is kind of flimsy and very plasticky, and I had to bring mine in for repairs twice under warranty (they sent me to a local Dyson authorized vacuum repair shop), where they removed some supposedly extraneous parts, which didn't seem to affect the performance. Dyson also sent me a brand new dust collection bin and filter at no cost.
The Dyson is much, much better than most $150-200 Bissell and Hoover vacuums I've used, but if I was buying another vacuum cleaner, I'd want something with much more suction power. I recommend getting something bagless, as it's really convenient to be able to grab a spare plastic garbage bag, to dump the dust and hair out into after every room.
If you're good about cleaning, you might want to consider an air purifier with a prefilter and HEPA filter, preferably washable. Mine is doing a nice job cutting down on some of the dust. I think my carpet gives off a lot of dust, though, so it's a frustrating battle.