For helmets, I have used Arai, Shoei, Shark, AGV, and Bell. I just got the Bell Star and haven't taken a ride in it yet so I can't really comment much on it, but I love the AGV and Arai helmets.
For jackets and pants, I'm partial to Alpinestars only because they seem to fit me best. I have other gear from Scorpion, Teknic, Dainese, Spidi, and Cortech.
For gloves, I currently use RS Taichi GP-Max gloves and Alpinestars GP Pro gloves.
For boots, I use Sidi Vortice and Alpinestars SMX-Plus boots.
The most important thing is to pick gear that fits you because if it doesn't fit or is uncomfortable, you'll be less likely to use it and that defeats the purpose of having gear.