I have pets and bought a new vacuum just a couple years ago. I went with Sebo airbelt k3 after hearing Miele had gone down in quality and I love it. This vacuum fixes every single annoyance I've ever had with a vaccum:
- the canister rolls easily on carpet
- the cord retracts perfectly every time and rachets out as you pull the canister
- it's easy to take apart to clear clogs and even has a little spring flap behind the brushroller to quickly clear the most common place a clog will get stuck
- the roller is trivial to remove and clean
- the bags are easy to change and hold a lot of dust and pet hair before you need to change them
The K3 is a little out of your price range but the K2 and E2 are a bit cheaper. I will say that if you've got a lot of thick carpet, it's worth investing in a vaccuum with a powered brushroller like the K3.
If you haven't, make sure to give it a good oiling.