I might as well throw out there the only custom moveset of mine that I've had better-than-expected success with, and that is the Amnesia-Counter Registeel moveset.
Although you might look at it on first glance and think, "not practical," I think that in general, using Registeel at all probably isn't practical. However, I've killed more pokemon with this set than Curse Registeel, and it's definitely more useful than the nigh useless CB Registeel. And it's fun.
In fact, you'd be surprised the things you can survive and kill. I took down a Calm Mind Kyogre 1-on-1. And Aerodactyl, and Curselax, and a lot of other big oafs.
The times that it doesn't work (which happens a good bit, because the set requires prediction), people will laugh at you for having a stupid non-standard moveset, but when it works, oh it works very well.
Registeel @Leftovers
Trait: Bold or Impish
EVs: 252 HP, 252 Def, 6 SpDef
-Amnesia
-Counter
-Rest
-Seismic Toss or Thunderbolt or a strong physical move
The goal here should be obvious. Either switch in Registeel at a good moment, or save it for last if pseudohazers are being troublesome. Amnesia up against any special sweeper to lure in a physical sweeper. Then use Counter. Rest when necessary, and Registeel very much has the defenses to make GREAT use of Rest.
If a pokemon refuses to use physical moves, use the secondary attacking move. Seismic Toss is probably best, since it does decent damage to any non-ghost, but T-bolt does have its advantages, largely because it can paralyze and hit Gengar.
One of the best things about Registeel in general, and in particular this set, is that there are very few counters to it. Registeel with a good EV spread can survive any Fighting move or Earthquake (except maybe from Groudon), then OHKO the attacking pokemon with it easily, and rest off the damage. Registeel is a Steel type, so Toxic cannot stop it from stalling. Rest can stop status abnormalities anyway. Clear Body will prevent stat reducers.
In fact, the best counter against Amnesia-Counter Registeel is a fire pokemon. Even with Amnesia, fire will do good damage, and you won't survive a rest if you're getting STAB flamethrowered every turn. Gengar and Dusclops can stop Seismic Toss, so watch out for them, too. A strong reversal can probably take him down too, but there are ways around that.
But yeah, it can work if you predict well, and it can stall. So... yup. It's not like the current Registeel movesets are so awesome that there's no room for a new one, so I thought I'd just add my two cents.
