Whoa, thank you for the lyrics
Mitsukete Happy Life is an enjoyable song. It has a nice happy/sunny/kid-like tune to it, that made me feel happy too. However, nothing beats Yuki, Muon, Madobe Nite, since it sounded a little cold but has a very lasting impact on the listeners. The speech part (where Yuki's VA uses Yuki's voice), is simply the best part of all.
Now I remember which .hack//SIGN song Yuki, Muon, Madobe Nite's intro sounded like: Its the anime intro (but I forgot the damned title).