Welcome to the LIGHT!
Didn't you get a developer tools (xtools) cd with your system? Or were you fetching updates to the tools?
A couple things off the top of my head:
1. Put the Terminal program on your Dock by going to /Applications/Utilities and dragging it somewhere on the left side of the Dock. The Dock icons are aliases (or shortcuts or whatever you want to call them) so you won't have moved anything.
2. Get Apple's "X11" app, their version of XFree 86. It will integrate X-Windows with Aqua including OpenGl acceleration under X-Windows as well as 3-d acceleration of 2-d window contents (Quartz Extreme), something not offered by anyone but Apple.
Of course, any of your favorite Linux apps and utilities for which you can't find Darwin binaries should compile without much trouble. But there are a ton of binaries available.
3. Hit <Apple Key> S (Apple key is called "command") when starting up the machine to enter single user mode. Here you can run fsck (the hfs version) if you wish.
4. You're probably NOT going to want to format any drives using UFS; Apple's implementation is very slow and not completely compatible with the Mac stuff.
Apple's Hierarchical File System +, brought over from the "classic" Mac OS is pretty good and journaling has been added. There's a case-sensitive version and a case-insensitive version. You'll probably want to stick with the case-INsensitive version, believe it or not. It usually works fine, unless you have apps that have same-named files with different case. Obviously, none of the OS X or classic Mac apps will have a problem with case-insensitivity.
Why stay away from the case-sensitive version? It's brand new and (relatively) untested. Who knows what kinds of incompatibilities might crop up.
5. OpenOffice.org seems to work quite well on OS X under X11. You could even use the Unix version of (gasp!) Microsoft Office ("Microsoft Office v.X for OS X) if you wish. For a Microsoft product, it's real purty. Also, OS X's TextEdit, the gui text editor, will read and write .doc files.
6. OS X's Preview gui app shows .PDF files REALLY QUICKLY, much faster than Acrobat Reader/Adobe Reader.
7. OS X's Mail app (starting with OS X 10.3) shows HTML emails quite well and is overall a good email app. You have several other choices. There's Microsoft Entourage, part of MS Office, very similar to Outlook; Eudora, of course Pine and Elm, etc.
I could go on and on but at some point my *nix ignorance would show. I'm not really a *nix guy. I'm still a nuB. In fact, I was running Winblows (ugh) until a couple years ago when the governor of Michigan bought me an iBook (true story -- we go way back. . .).
As for Linux to OS X switchers' books, I'm not sure. Check out
www.oreilly.com (and
www.macdevcenter.com).
Have fun.
Doug