It really depends on the game. I'd rather be playing Sega Genesis's
Sonic the Hedgehog games compared to the 360's, but I'd rather be playing Oblivion than Daggerfall.
I mean, some old games are great, but some suck crap. Same thing can be said for the newer games. It also varies between the series. For example, in The Elder Scrolls, you go from this...

to THIS:

Also, all the newer Elder Scrolls games have been much smoother and easier. Everything is even and balanced in Oblivion and there are no useless skills. Like Daggerfall's "Be able to talk to imps" skill.
However, in some series, like Sonic The Hedgehog and Starfox (disregarding SFC) just went to hell with the newer games.