Warning: I had to go through my blog archive to make sure I didnt already talk about skill challenges, but I might have missed it anyway. If I did, sorry in advance.
Skill challenges, and to an extent traps, are a mechanic that I dont use very often in 4th Edition because the former is new, and the latter had a lot of flaws. I've used skill challenges before when I ran Keep on the Shadowfell and it didnt seem to take. Mostly I think it was the presentation: I announced to them what was going on (a skill challenge, yee!) and how the whole thing worked. Treating it like combat, they just rolled the skills they were best at until the required number of successes was reached.
Awhile back when I was running Age of Worms in 3rd Edition, I did something very similar. The players had rescued a NPC in The Hall of Harsh Reflections and were invited to dinner at the Cloudy Dragon in Skyway (oh yeah, this was in Eberron). I mapped out ten things that the NPC liked, and ten things she didnt like, based on stuff that I knew about the characters and players. If something wasnt on the list, I'd wing it. The idea was for each player to interact with her with extensive social role-playing, and at the end I'd tally up her resulting attitude to each player.
There wasnt a list of primary skills that they were aware of. The players didnt declare that they were going to use a Diplomacy roll, but would say or do something and then I'd call for a check. Sense Motive would let them realize if they were saying something that was offensive or that she really liked, Bluff let them remove a bad tally if they realized that what they just said/did was bad, and most of it was Diplomacy, Perform, and various Knowledge rolls.
My group liked this a lot, and I think it was because they didnt really know all the details behind it. In a skill challenge any player that has read one, or even the DMG, knows that three failures ends the whole affair. They also would know that you have to get at least four to win. With that in mind, its easy to see how competitive players can look at it as just a grind: use your best skills over and over again regardless of the situation or context until you rack up enough "hits" to "defeat" the skill challenge.
I went through Mike Mearl's skill challenge archive last night while helping Red Jason out on another skill challenge. I had created a basic skeleton for a few in Songs of Erui, but felt that a better crash course would be extremely helpful since he wanted it to look very official. Some things that I liked about it are that he likes to make sure there are a lot of skills to use. In the DMG, many have 3-4. For Mearls, four seems to be the bare minimum. Now, if you dont want to "just do the bare minimum", a better target number is five. His advice is for there to be as many useful skills as there are party members + 2.
Another trend that I noticed is that a failed skill challenge shouldnt grind the campaign to a halt. If your skill challenge absolutely must be bypassed to continue, then you need to rethink it. In The Forest of Bones, the party will have to navigate a forest while looking for a ruin. Its going to be a skill challenge, to be sure, but it will be broken up by combat encounters. The results of skills used during its progression will determine if they get ambushed or injured prior to the combat encounter (such as by losing a healing surge or taking ongoing poison damage from contacting toxic plants).
Skill challenges can and often take up more than a few rounds. The above example would likely take hours for them to complete, and as you can see wont all happen in sequence. It breaks up the typical skill challenge template since I'm shifting gears between skill rolls and combat, but in a (hopefully) good way.
I'm also going to approach things differently next time by not even telling the players that they fell into a skill challenge. Even if they figure it out, I'm not going to tell them which are key skills. Instead, I think I'll play it as I did before by calling for skills that make sense in the context of the situation and their actions. Running from guards and want to try and hide? I'd probably call for an Athletics or Endurance to get some speed, and then a Stealth to hide. I think that this approach might stop players from not participating just because they dont have a primary skill, but would also encourage prompting from them instead of me asking for a skill roll.
This is something that Mearls mentioned in his articles: the players should be the aggressors. When I ran that social encounter a long time ago, the players were the ones taking the initiative by talking. I just called for rolls after the fact. I think that it does make a difference instead of you calling for a skill roll and just having them roll to start chalking up successes. I'll just give this a shot and see how it goes. If not, its back to the drawing board. My group had fun with this sort of thing in the past, so its just a matter of adapting them to suit their tastes.