Heya James...
As to which model's the best, you'll get all sorts of opinions that without exception will coincide with whichever model the author's got. As Greg pointed out they're basically the same bike... the mechanical differences amount to different handlebars & seat, single or dual front disks, spoked or "mag" wheels, and if you're getting this year's model one has about 60cc's more engine. They also have a different "look"... the speedmaster's a blacked-out boulevard bruiser, and the america's a chrome cruiser. Ride them both, look at them both, see which one you like best. Maybe get some brochures and stick pics of the two models on your wall for a few days and see which one catches your eye more. However if you decide on the America you'll want to change the tyres as quickly as possible (maybe order it with different tyres) as the Bridgestones that Triumph put on the Americas are pretty average in the wet. The Speedmaster's Metzelers are much better.
Personally I wouldn't want to leave any bike in the rain... at least get it a cover. Leaving a bike wet (or worse, wet and muddy) will promote rust and kill the finish on the paint. It also makes it more available to thieves.
I don't have any transport other than my bike, and have gone to the point of putting a tow-bar on it and getting a cargo trailer for shopping, camping etc. I've done over 35000km in 2 years on it, and it's been pretty much flawless other than a minor wiring issue that the dealer quickly took care of under warranty.
As a first bike there's much worse choices out there - these are well behaved bikes with a nice low centre of gravity and are pretty forgiving. They're big enough to do pretty much anything that's asked of them, but not so big that they'll monster a newbie.
Have fun choosing, and let us know what you decide.
Matt
