Do you have a basic budget and configuration set in mind?
Screen size?
Proc speed?
Ram size?
HD size?
Luxuries (ie - DVD/CDRW/LS120)
Video card? (Geforce2Go, Rage Mobility, S3)
Mouse input type? (trackpad as opposed to mouse pointer)
I usually prioritize in the following manner:
Monitor size and type
Mouse input type
HD size
Ram size
Proc speed
Video card
Video card is on the last of my list cause most are capable of the basics, and I don't expect it to be a gaming card, nor do I use it for gaming. For DVD perhaps some consideration is needed?
Proc speed is usually another item I don't look at too deeply, so long as its of a decent speed. Any celeron 366 and above is good, so long as it can handle what you need to do plus a little extra head room. For DVDs, look at 400mhz and above. Not too much to look at here, unless again you're considering gaming. Should do just fine in basic office functionality.
The monitor size and type is my single most important factor, whether its for a PC or for a lappy. You have to stare @ it consistently, so don't make it rough on yourself. Standard TFT Active Matrix is good. Never go cheap on the screen, it'll come back to haunt you later. 14"ers makes it easy on the eyes, go for 15" if budget allows. Forget 12-13"ers, too small for comfort, IMO. I've used a 12" lappy before, it really does put a strain after extended use. The display can either make or break your laptop experience.
Another very important factor is the mouse input type. There's basically two types, the trackpad and the mouse stick. I've wanted the trackpad at first, but after using the mouse pointer I would never go back. With the stick its easy to navigate mostly anywhere without much finger motion. But with the trackpad I find myself scrolling and scrolling and scrolling, and having to constantly lifting my finger to and fro, pretty annoying and inefficient.
HDs are upgradeable, so only go all out if budget allows, otherwise around 10gigs should be fine. Allow for more room if you're going to be dual-booting. Also consider the types of apps you'll be running on it.
Ram are pretty cheap also and easily upgradable, stick with the standard 128 (adjust for more depending on OS type) unless budget allows.
A burner in a lappy? Perhaps, if its going to be your main system for work and net use, otherwise skip it. DVD? Personal preference. Mobile entertainment is always nice, especially when you got kids that travel with you
I use my lappy as my main workstation now. Everything else on my desktop is only there for the peace of mind knowing if I need to use it it'll be there (Geforce2, Plextor 12/10/32, SCSI Atlas 10K II U160 9.2Gig HD, 17" KDS AG, 256 PC133 SDRAM, etc...).
Here's what I've got for a basic lappy:
Toshiba Satellite 2595xDVD
Celeron 400
14.1" TFT Actix Matrix Display
128mb ram
6.4gig HD
DVD Drive
Pluckster