I still carry the iPod touch with me for portable things. I have "things" on the iPod touch, but haven't bothered with installing that on the iPad. My "to do" list needs to be in my pocket.
I subscribe to a lot of podcasts... The iPod touch is better for listening to these because I can plug headphones into it, and walk around with it. I can play them on the iPad, as the speaker makes it work kind of like a radio - it's loud enough. but, it's just as easy to plug my iPod touch into my stereo. Plus, I don't sync the iPad very often, so it doesn't usually have the latest podcasts I'm interested in.
Anyway, I use the iPad a lot, but for different things than the touch. Mostly, I use it for surfing, and doing quick e-mail checks. Basically, anything of length I need to read is far better on the iPad, and it's a lot quicker (and more fun) than going to my desktop or laptop. Plus, I've found a few games I like...