I loved the old random encounter tables. There was something just so full of promise about them. I used to peruse the massive encounter tables at the back of the 2nd Edition Monstrous Manual (you'd get a new set of tables per expansion) in order to get ideas for encounters... and in fact, still do, on occasion, since I seem to be the only person left in the world who actually liked the ring-binder approach to monster manuals adopted by TSR back then. They were divided by terrain as well, so you could get an at-a-glance snapshot of the kind of beasties you might want to throw at your players as they moved through your campaign world.
Which is to say I use random encounter tables for everything except what they're intended for: the actual rolling of actual random encounters.
Random encounters suck. One of the reasons is their unpredictable effect on the party's resources and the knock-on unpredictability in the campaign (which I've discussed below); another one is that they tend to be a bit bland, simply because they're designed to be dropped in at a moment's notice; yet another is that they're essentially, well, random, and have very little to do with the party's constituent classes, location, goals, etc. From the player's point of view, dying from a random encounter seems like a very bad deal, and not very heroic at all.
A good DM will be able to take a random encounter and drop it seamlessly into the game as if it had been there all the time; someone who aspires to be that DM will cheat, by using random encounter tables as seeds for planned encounters that he can set up beforehand.
I'm that guy.
When I expect to have to give the party something to do while they're exploring a dungeon or traversing the wilderness, I'll check the random encounter tables and expand one or two of the best ones into full-blown tactical or roleplaying challenges. A good example that my players probably won't enjoy telling you about is where they were ambushed by several megaraptors in a field of lush, tall grass... and yes, I was inspired by Lost World. The random encounter table simply said 'Megaraptor pack (1d4+2)'. Okay, good starting point. I knew they were in grasslands and that scene from Lost World almost immediately popped into my head... what could I do to recreate that? Was an ambush feasible? What would the sorcerer see when she inevitably flew up above the grasses to get a better look? What would visibility be like? How would the minotaur's scent ability play a part?
A good DM would have been flash-inspired with all of these facts in a blaze of prodigious DM-osity simply by rolling '05-15' on the encounter table. Not being that DM, I had to put an extra twenty minutes of thought into it... but the result was a fun, dangerous encounter, the first few rounds of which caused the party no small amount of controlled panic.