kateleestar - you might be better off with a pedometer if you are curious how many calories you are burning doing your every day stuff.
I find Nike+ is great for a walk but I doubt it would be very good to keep on everyday, all day long. For starts - your iPod is going to die.
I love my Nike+ and I love my pedometer - they are both great for very different things. I honestly thing my pedometer is a little more useful, I just tuck it in my pocket or purse and forget about it. My Nike+ only comes out when I am specifically going for a walk/jog whatever. I have a little clip for my Nike+ too for my runners, because I don't wear Nike shoes.
You also have to be very careful about how the Nike+ is attached, otherwise is does not read correctly. I had it on wrong once, and it said I went 1km - I put it on correctly and did the same walk the next day is was 3-4km!
I have this
pedometer - it has great reviews and I have been really happy with it. I like it because it works in a purse, pocket, bag, etc. There is also
this version that lets you upload data to your computer.
I have an account on walkertracker.com and I just use the cheaper pedometer and enter my data manually - when I am using it! Been lazy lately.