I'm one of those "newbies". Got my first bike, an 07 America, in April. While shopping for a bike, my riding friends at work all told me to get bigger to start out. My friend with the 750 Shadow says it was a great starter bike for maybe a month, then he started wishing he'd gone bigger.
Starting with an 500lb 865 was a little intimidating (after that little 250 at the MSF course) for about two days, then I was comfortable.
And the America is more than capable of getting out of it's own way...or out of that inattentive semi's way more importantly.
After a few months I started to get that "wanna go faster" feeling - new pipes and a jet kit made her run like a scalded cat and I'm happy now.
Oh and Gretsch - I can relate, I'm 36. I guess it's a good age to start riding cause we've figured out we're not bulletproof. Anyway, I do hope you get a Triumph, I think it really is the best (and coolest) choice out there - but whatever you get, good luck and enjoy. It'll change your life.