It feels vastly different when you can point and shoot instead of aiming with a control stick though... I don't really like RE4 with a standard controller as it's not really a survival horror like the earlier game, as such the original RE4 is kind of an action game with broken controls... but with a Wii remote it makes it into a good game (though yes it can still be clunky at times)

Fire Emblem: Radiant Dawn is a marvelous experience... much more if you play first Fire Emblem: Path of Radiance that was a Game Cube title and you can play it in your wii if it is backwards compatible and later import your file in the Wii one.
My only recommendation before you get lost in its universe is to get rid of the fighting animations (easily done in options) for the battles to be more a bit more dinamic.

By the way: go get Tales of Symphonia for the Game Cube too!

Monster Hunter Tri
Metroid Prime Trilogy
Silent Hill: Shattered Memories
Mario Kart
and Eternal Darkness for GameCube

I suggest just getting MP1 and MP2 via GC and just buy MP3 by itself.

Saves ya the money and time looking for the Trilogy.

Also you get to suffer what the true MP2 Hard Mode was.

You life in Austria. So you should add The Last Story and Pandoras Tower on your Wii-RPG-List. Both are great games.

I found the Metroid Prime trilogy for 60€ on Amazon, I think I´ll purchase it

You won't regret it!

Galaxy (both)
Pikmin
Mario Kart
Mario Party 9
RE: 4
SSBrawl
Okami
Mario All Stars
Pandora Tower
Monster Hunter

Little King's Story and Muramasa can keep you entertained for very long time.

Try Wind Waker, it's a gamecube game but it's a true Gem. I also support the MP Trilogy bandwagon. Pikmin for GC are also gems try to pick them up in whatever form (new play controls, good ol' cube).

Give sunshine a try someday if you're really bored. The water dynamics are lots of fun.

And if you've never played Melee, pop in a gamecube disk into that Wii and you'll be glad you did.

Also, try OgreBattle 64 on the virtual console. I am not a fan of grid-based RPGs, but this one is a beauty.