look at the GCN library then look at the N64 library, there are far more standouts this generation than last, games that come to mind from the N64 gen include Mario 64 and Ocarina of Time, yes there were alot more good/great games than that, but that's just what stands far above the rest, THIS generation how ever we have Wind Waker, Metroid Prime, Eternal Darkness, F-Zero GX (how they pulled this game off i don't know), and this generation isn't over yet. and before you start shouting yes i realise f-zero gx was made by amusement vision, a development studio of Sega, but Nintendo would still have overseen the production, it IS their franchise after all.
either way i don't think Nintendo has lost it's touch at all, not only is it still putting out FUN games, it's increasing the amount of fun to be had on it's console via lending of franchises and strengthening of it's third party support. go nintendo.