A "post-mortem" glance of sorrow at your choice besides, congrats on the purchase. I use a Fender 25 watt amp (college apartment) for practice, I think it's good for that. When I get back in a band again, though, I know my amp will be TUBE. If you love the old classic guitar sound, I think it's invariably the way to go. Im just not a fan of solid-states. I also second the anti-Marshall sentiment, I think they are good hard rock amps but I do find them to be mediocre clean. For me, my dream amps would be a British Hiwatt, a Fender Twin, a VOX AC-30 or anything Mesa-Boogie.
*another note on your amp choice: if you live with your parents or anywhere noise sensitive, whether you get a loud one of not, try to get one with a headphone jack. You can play any time of day or night and not worry about keeping people up. It's not the most desirable situation, obviously, but it'll get you by.
Also, I personally notice a night-and-day difference between MIA and MIM strats; I have a Highway 1 and I played a MIM at GC the other day, and the neck seemed twice as thick as mine. But mine's also been setup the way I like it and most other electrics feel weird at first.