My one beef about combos in Smash is that they technically don't exist.
Yes, that's right. The standard--and universal--concept of "combos" in traditional fighting games (i.e. SFA3, MvC, Tekken, GGXX) involves a set and established sequence of button presses that result in a series of quick, (basically) inescapable consecutive hits that leads to a noticeable amount of damage inflicted. The concept of combos in Smash, however, is non-existent simply b/c whatever sequence of hits you happen to invent probably won't work due to the sheer number of variables involved w/the character's physics.
For example, let's say you're Luigi, and you're fighting Fox, and then pull off this "combo:"
grab -> u-throw -> d-smash -> d-smash -> shffl'd n-air -> f-air (finisher)
. . .it seems fine. Except, consider this: The increased knockback as damage increases means that at a certain percentage, this combo will fail to work given that the opponent will be hit so far away by any of these hits that he can eventually recover, jump out of it, sex kick out of it, etc.
Also consider that the opponent's weight/falling speed affects this combo as well. Luigi's vertical launchers (and this particular combo) works damn well on fastfallers (read: Fox, Flaco, CF), but if you're trying to do this on floaty characters like Samus or Peach, then you can forget it. They can sex kick/jump out of this immediately, especially given that they don't fall fast enough to be combo'd by the sequence described above.
Finally, there's the issue of DI--Directional Influence. Hold the control stick up and away from the attack exactly when you're hit, and you'll drift in that direction while stunned. Good DI--which is a technique that few smashers really care to learn, unfortunately--tends to screw over many combos that people set up.
Given all these diverse variables that exist which can potentially screw up whatever combo you invent, you can see why I'm saying there's no true combos in Smash. You may view this as a matter of semantics, but realize that there's rarely, if ever, a sequence of hits that works on all characters. It's this fact--that the physics system in Smash forces people to invent and improvise their combos on the fly (kind of like GGXX, but different)--that makes Smash so unique.
The only true combos that exist are chaingrabs and infinites. Chaingrabs, like Shiek's d-throw on everybody, Ganon's d-throw on Link, and Mario's u-throw on fastfallers are nigh inescapable and can go on for quite a bit, even if you have good DI. Infinites (courtesy of Fox's Shine, and the IC's grab game) are, as implies, impossible to escape unless the person doing the infinite screws up. . .which is very likely, given that both require a large amount of technical skill.
However, having a Smash combo thread on this board would be nice, simply b/c Smash is such a great game, and it needs all the PR that it can get. . .so I'll post some combos later.
btw, the Luigi one I put up there is actually a "legitimate" one; it needs to be done on fastfallers only (Fox, Flaco, CF) at about 20-30%, and you have to make sure to do every attack ASAP and shffl the sex kick and/or follow DI. It's not perfect though; I'm sure they'll be able to sex kick/jump out of it somewhere. . .but it's certainly a feasible one.