(EDIT: Forgot to mention - I mean C&V VLW's)
Figured I'd give the underrated machines a go:
5. Marinoni anything (EDIT: Debatable):
I'll be perfectly honest, I've never had any hands-on experience with one. I'm placing it here purely after reading what I've heard about them - namely that every single person who has owned one says they ride particularly well, and that all of them seem to show excellent workmanship. Furthermore, they seem to be, on the average, reasonably affordable (definitely so in comparison to most Italian machines).
4. Japanese-made "Series" PDG Paramounts:
Oversized, lugged cromoly steel frames with completely functional Shimano drivetrain systems - some higher end then others. Depending on the model, one can conceivably pick one of these up for under $300. What isn't to like about that? Furthermore, if you think all Paramounts ride similar to the second-gen models (i.e., overbuilt and often "dead"), you might think differently after riding one.
3. Miyata 710:
How can you argue with a bike that comes stock with a triple-butted cromoly frame and Suntour Cyclone, and is often found on Craigslist under $250? You can't. Sure, it has that unmistakable Japanese-build look to it, no lug thinning, thick fork crown shoreline, boring dropout-to-stay treatment - but so does a high-end Team Fuji for twice the price.
2. Peugeot UO-8:
I debated on whether to consider this underrated - many of the folks here on the forum have caught onto the fact that Peugeot's high-tensile bargain 10 speed is a solid, inexpensive little frame. Furthermore, it isn't as heavy as one might think it is when upgraded with the right components (a simple Suntour FD, RD and shifters can solve the main weakness of the '70s-era UO's - the Simplex Prestiege groupset). Did I mention that they're plentiful? They might as well be the French Schwinn Continental - without the built-in boat anchor.
1. Raleigh Super Course (pre-1983):
I probably don't even need to introduce the Super Course. It was probably Raleigh's best-selling model with 531, and we all know what it is. It doesn't matter that the earlier models have stamped dropouts, and that some of the later '70s models were sloppy (like all late '70s Nottingham Raleigh products). They ride well, and you can do virtually anything with them (ask nlerner, king of Raleigh SC's). Best yet, it isn't entirely impossible to find one cheap - regardless of whether it is a first-gen SC, SC MkII, or the later third-gens. They're plentiful, reliable, versatile, and inexpensive.
(There are many others that I'm no doubt omitting. I can't think of them right now, and I'd probably be here for hours trying to figure out which belong in this list - it would end up being a top-10).