I actually picked up the 111 DMU a week or so ago to run on some scenarios I got for the Port Road (see how they suckered me in with their freeware

) I like it a lot.
So, I just bought Ohio Steel, and will install the SOO line, Bay of Quinte, and Eagle Ridge (one I found myself), since all of those use assets from Garber's routes and the 3DTrains scale stuff I bought. The C&O Allegheny is also intriguing and I'll check that out as well.
My wishlist now has Portland Terminal, Ft. Kent (perhaps C&N also), Challenger, Big Boy, GTrax Northern, possibly their Genesis, WCML (perhaps E-G also), SD70M-2, GP-9, and Seattle and King's Arm Deluxe when they come out. That seems to be a great list. I'll pick up UK Locos as I need them for routes and scenarios as was suggested. If some "must have" bit is missing, let me know. And thanks for all the responses! Should keep me busy for quite a while, once I get it all bought! I hope to make a real dent on the list when the big sale comes.
I hope this thread has been helpful for others as well, if I'm not the only noob out there that doesn't know this stuff yet. Even with the problems, I'm sure enjoying this sim.