100% Rhydon : '(

That sucks but I feel you, I've got an Alakazam 100% with Confusion/Dazzling Gleam. :(

I mean at best you're still gonna get the highest CP possible, that's something at least.

I wish we could train and teach our mons new moves.

It does not lol... MS/Eq is the best for him. some say stone edge, but rock is a huge counter to fire/fly type, and MS does reduced dmg to fly, this makes the moveset's use very limited, because golem can get double rock moves.
Magahorn is not a terrible charge move, but RS is very bad with out stab. So keep it for collection and dont waste dust.

He has another evolution in Gen 4, so there may be hope for him yet.
http://pokemondb.net/pokedex/rhyperior

Well Rock Smash will probably still do okay against Snorlax even without STAB as a fighting move... Not ideal though. Megahorn still does okay damage.

I hatched a 100% one (my only 100% hatch so far) and it's sitting there unevolved as I've already maxed a MS/SE and invested a fair few Candy in a MS/EQ.

You could power him up as defender, at least you've got some protection if anyone tries to attack with grasses...

No worries, Rhydon sucks anyway

Had a high-level 93% Rhydon that evolved with RS/megahorn also. Candy was rare. Was so pissed i vowed to forget about him. Then the buff rebalancing came and I got even more pissed. But then as luck would have it, a Rhyhorn nest appears in my town!!.... evolved about 7 Rhydons with good movesets. More than made up for the disappointment. RS/Megahorn actually came up fairly often. But I had the luxury of just transferring them away this time. Pray that you find a Rhyhorn nest in the future.

Word... I received the exact same gift lol

What level is your R?