List of popular masks
Events/Avatars - I owned a set of the pre-09 events. They were uber comfy, and big enough so that they covered loads. I personally moved away from them because the combination of my heavy breathing and getting hot caused them to fog in the woods. This was only a personal problem though, nothing to do with the mask. They're great masks and people love them. I did, too. There's a lot more venting on the ZN events, which would help. Comes with a nice headshield attachment.
Dye i3 pro's - Dye's older model, still in production. Very big and (I've heard) very comfy. No quick change lens system though.
Proto Axis Pro's - Owned these. Very comfy and are quite big. I felt they were a little open around the jaw, but that's just me. They just came second to my personal favourites. Sold to a friend who loves them.
JT Proflex - Another very popular one. They're big, very customisable, and generally quite comfy. I have owned a pair, but sold them on because they weren't to my personal preference. Some people say the soft ears leave a bit of the ear exposed, but that's only something I've heard. There's also no quick change system.
Vforce Grillz - Owned these as well. Gorgeous looking and VERY comfortable. Very breathable, and large enough to feel well protected in them. Loved them, but the pair I had fogged up on me so much the first time I used them. Sold them on because of it. Was probably just me on a hot day, but hey. Some people swear by them.
Dye i4's - Own these still, and are my personal favourite. These are very small, but I feel that they don't offer any less protection due to how close they sit to your face. They have never fogged up on me, and are comfy as hell. Love them. The Grillz, Proflex and Axis pro's were all sold on because they just came second to my i4's.
Now, I'm very biased. But this is my list of popular and very good masks. I'm sure any of these will suit you fine, but, quite frankly, there's no substitute for trying them on yourself. I've been through my fair share of masks, and after it all I know what I like. It's very personal.
I'll agree with what's said. Event's are a safe bet. I'll also throw the i3's out there, as they're massive.