I have the Gateway with 2 of the 12's.. its no big deal at all, get the 12, really makes a huge diff on battery life, between the two i have bout 7hrs bat life.
As for carrying it around, you'll need a good sized bag, its a pretty decent sized piece of machinery but depending on how big or little you are, you'll either find it no big deal, or noticeable. I got a case with wheels that doubles as a backpack and everything else from Taurus. I carry mine all around the country, np. The wheels REALLy make a difference if you're fully loaded with gear or books.
As I've posted elsewhere, tho, I have 2 of the Everex XT5000T's from officemax, and unless you're into serious gaming, for 699.00 its impossible to beat that bang for buck, or even get close. You'll need another battery to swap in tho, but that will get you about 4 1/2 hours. For a Wow, or LOtr machine, BF2 etc. even up to OBLIVION on medium/high settings, the Everex does just fine with its 7600 Go as opposed to the Gateway's 7900GS, and the Everex has 2 hd bays...and a better looking screen, no kidding...freaks you out what a great deal the Everex is. I ended up buying two of em, and still spent far less than i did on the one gateway..and I got a helluva deal on the Gateway...so....pick your poison
had no trouble at all with the gateway which is very sturdy, but since i received it, i've spent all my time on the everex.
seer