clifchamb — Definitely on target with MA's playing on Fair Warning, especially "Mean Street," possibly VH's finest recorded moment. Also kudos for mentioning Eddie Jackson and his tone on "Jet City Woman." Great stuff.
PFDarkside — I agree with you regarding Cliff Burton as being not overrated. I think the only reason people regard Cliff Burton and Randy Rhoads as overrated is because they were killed after only a couple or three albums each. I still say they were on their way to changing music in a big way.
Some more underrated/overlooked bassists:
Jon Camp (Renaissance) — Check out both volumes of Tales of 1001 Nights to hear what I mean.
Muzz Skillings (Living Colour) — Talk about a bassist who covers the spectrum with his playing and you gotta mention Muzz. Full o' flavah!
Felix Pappalardi (Mountain) — I don't know why he isn't emulated by more bassists, unless it's because he's connected to Jack Bruce (Felix produced Cream) and thus gets sent to the back seat. But Felix was great, and his vocals were awesome, too.
Dave Ellefson (Megadeth) — Here's a guy who understands what it means to play in the rhythm section with authority. Nothing really flashy, but without him Megadeth would have been just mega-dead.