The question with this practically yearly thread is: what do you want, luxury, or loud?
For luxury, I don't see anybody better than BU's fancy Agganis Arena. It's the newest in Hockey East by quite a bit. But is that what college hockey is all about?* But I don't find it feels like a college hockey game there, too often; it feels like you're in a professional setting. I like freezing my a** off, having opposing fans yell at me, and having the band play as loud as they can regardless of tuning.
For atmosphere, student involvement, and fans proximity to the ice (which is what epitomizes college hockey for me) the best arenas are Lynah, Matthews, and the Alfond. I've always enjoyed Lawler Rink (Merrimack) because it's so small -- and now, their fans are really into the games, too (they boast something like 70% of their student body attends . . .) The Alfond, structurally, is a dump. They'll sell you a ticket for $25 but you won't be able to see 1/3 of the ice, or the scoreboard, etc etc . . . but go up there for a game when UNH is in town, and it's still one of the best places to see a game.
This thread needs another mention of just how great Matthews Arena is. Kudos to whoever designed the renevations - they kept the old-time barn feeling, with the balconies hanging over the ice, while giving it a major upgrade, comfort wise. I haven't been to Conte Forum in a while, but always thought the sightlines left something to be desired. I don't like the gap between the front row and the glass - I like to be right up on the action.
*I've never been to the REA, or any arena out that way, so I really can't comment.