Just to answer very very simply: a lot of fun... :)
I haven't bought that many games on Wii yet, only some of the best titles, but i've rented many games for a year now, and i've played more in 2007 than any of the last 10 or 15 years...
And so, it's a very reasonnable Wii budget for me, as each rented game costs me only $10 or so... for my first $600, i think i actually played something like 20 Wii games: 15 rented and 5 bought, plus three wimmote/nunchucks for multiplayer fun with my kids... not bad at all... :)
"A beautiful drawing in 480i will stay beautiful forever...
and an ugly drawing in 1080p will stay ugly forever..."