Not American, but I can give you some $NZ prices for the things you ask about. Wellington and Auckland are pretty similar in terms of prices for things, so I won't differentiate between the two. Movies (except on Tuesdays ($8-10) and in budget theaters such as the Regent on Manners ($10 tickets) are around $15 a pop, although you can pay more by getting flash seating. Live music - there are places which do this for free (Molly Malones in Wellington) but on recent nights out in Auckland and Wellington, I paid between $10 and $15 to see local bands. I'll be paying $90 or so to see Sonic Youth.
A coffee comes in at $3.50 for a flat white or cappucino. A beer $6 - in any sort of cafe or bar with any pretentions to class, it will be $7.50 (tap beer not included). A meal in a cafe will start at around $8 for a basic main (mostly in Asian cafes - Wellington has great Malaysian food, Auckland has Food Alley and a wonderfully shabby yet cheap quasi-Chinese cafe on Wellesley Street West, open till 3:00). But this is at the bottom end - lots of cafes are more in the region of $15 for a main, and of course, after that, the sky is the limit. Or you can do the kiwi thing and have fish and chips - here in Dunedin, it is 2 fish chips for $4.20, up north in the big city, they charge a bit more. Breakfast can start at about $8 as well, but for a cooked brekkie, $12 is more like the bottom line these days.
Hostel rooms are $25 (dorm) $65 (double), hotels start at $75 in the FormuleOne in Auckland and $85 in the Comfort Hotel in Wellington. Internet in Wellington is $4 (sometimes $3 if you find the right place) and in Auckland $2 an hour ($3 if you want LCD screens and clean keyboards). Bus in Auckland was $1.60 anywhere in the CBD/Newmarket/Ponsonby region.
