While I respect the opinion of others on the subject, I have been very satisfied with my Dell Inspiron 8100. Consumer Reports puts Dell #1 in support, and like IBM they build from reliable off the shelf components (well known names, too, not foreign or out-of-biz tomorrow names).
I would second what the others have said about buying what you will really need up front; laptops are not as easy to upgrade as desktops.
Some things to look for are connectivity to a port replicator (enables you to quickly "plug in" to printer, larger keyboard, monitor, sound system, etc. at home\work), 2nd modular bay (to exchange CDR drives, ZIP drives, 1.44 drives, etc.), and reputation\warranty of whoever you are buying this from. I would rather spend a little more and go with a big-boy who will take care of me when the going gets tough, as opposed to someone who subs out their support or may not be in biz next year.
Also, if you are looking for a lot of photoshop working, check into a larger graphics card (32 or 64 meg), as this will in many circumstances accelerate your rate of refresh, particularly noticable in large files. A word of caution, however; my wife is a Senior Art Director with a major corporation, and she would NEVER do any of her graphic work on a laptop; just not the appropriate platform for large, professional projects.
Whatever you do, Good luck and have fun with it!