Interesting replies...
What do you mean by "no converting?" No converting for what? Just to store it in iPhoto and play it back on your computer? Is that all you want to do?
The Canon TX1 (older camera) does mjpeg/avi in HD (720p) which can be stored and played from iPhoto, but the files are huge and it's form factor is odd.
The Panasonic ZS3's AVCHD lite format cannot be stored and played back simply through iPhoto. iMovie now handles AVCHD lite, but you have to import them through iMovie, which converts them to an intermediate format. Not what you said you wanted. But the ZS3 also has an option to record HD in mjpeg/.mov files which can be kept in iPhoto and played back by just clicking. The Panny LX3 can do the same, but is a bigger camera. The issue, as with the TX1, is that these .mov files are similar to the TX1's avi formats (both use mjpeg for compression), so the files are HUGE.
Canon's SX200 will shoot h.264 movies wrapped in .mov, and they can be stored in iPhoto and played back there, too. The h.264 movies also benefit from more compression than the mjpegs, and therefore create smaller files. I believe a couple of the newer Canon SD series (SD960 and SD970 according to dpreview?) also record HD in h.264 in the same way, so they should behave in the same manner. h.264 takes a little more processor power from your computer to play, though. If you have a newer Mac, you'll be fine. If you plan to edit the movies or share them with other computers you could have issues. Editing and re-encoding from h.264 requires time and processor speed, and if you send copies to friends to play on their PCs or older Macs, they could have issues. Newer Macs (by newer, I mean any Core 2 Duo since the white intel iMacs -- my 20" white 2.16GHz C2D plays them fine) will have no issues with playback.
Hope that helps.