It would be great to see some Irish Micro start canning. Definitely a more green option as compared to glass as the reduced weight means less fuel used in transport.
I've had some great craft beers out of cans in the US; the most recent one being Kona Brewing's Coconut Porter. (Amazing stuff, I've been trying to track down a can of for YEARS.)
You definitely don't need to worry about the beer getting light-struck or "skunked" either and the O2 levels in canned beer are almost unbeatable.
-I'd love to compare the cost of a double evacuation long stem automated glass bottle washer/filler vs. the equipment required to can to look at financial feasibility in more detail.
Adam