More dumbfvcks who don't know what they're talking about in this thread:
TIFF is good, BMP is good, RAW is best.
Avoid JPEG, GIF, PNG, etc.
TIFF, BMP, RAW, and PNG are all lossless formats. TIFF and PNG have lossless compression options. BMP and RAW do not. There isn't any particular advantage to any of these lossless formats over another for RGB images. Saying that RAW is better than TIFF makes no sense. Professional graphic artists have been using TIFF iamges for years in the highest quality printed documents. RAW isn't even really a format, it's basically a memory dump from whatever's in the camera. The only advantage to it is that it's really easy to write software that can read or write a RAW format.
I personally leave mine in PSD format. I know there's a little loss but nothing I can really notice and I'm pretty anal when it comes to picture quality and degradation due to compression for project pics.
Photoshop PSD files are not lossy. If they were, Adobe would have gone out of business long ago. Professional graphics people wouldn't tolerate that. I don't know who the hell told you that PSD files are lossy...
Your camera saves JPEG files. There is no type of conversion to another format that is going to make them look better than they already do. In fact, you could actually lose data if you use a poor JPEG decoder. JPEG images are similar to MP3 files. They don't look (or sound) better just because you convert them to lossless formats (like TIFF or CD-A). There is no magical "get back lost quality" feature of lossless formats. Once the file is saved in JPEG format, all the data loss that has occured is permanent. Converting your files to TIFF or something else will only serve to make the files larger. You are best off just keeping JPEG files.