@[member='SLiV3R']: unless you go with outdated guides (none of which are recommended by anyone on this forum), you can play retail games without problems.
I'm not sure what you mean with lagging in virtual console games. As far as I know, they work just as well on your wii (in fact, the loading is slightly faster...but since the virtual console games are 8- or 16-bit games, that's just a matter of loading it into memory). Available space is the only real bottleneck. But even that is only if you want to grab just about any virtual console game out there.
To be honest, it's better to use an emulator for virtual console games. Less hassle, and far more options (save states, to name one).
Modmii is absolutely the best tool to start with when not knowing about things. It gets the latest files and gives a good deal of information without flooding you in technical details. (in fact...I'm a bit jealous that modmii didn't existed back when I started working on my wii
).
Oh, and a small tip: if you want to play gamecube games...make sure to look for a version that still has the ports for the controller and memory card. Packages like the family pack don't have those. And even homebrew cannot work around that: for gamecube games, you WILL need a gamecube controller and a port to plug it in.
@[member='Nxenz']: depends. If you want to hack your wii...see my reply to SLiV3R. But "need"? No. The wii works fine from the box. And I would suggest at least enjoying some retail games before voiding your warranty by hacking it.