I have a Dell Inspiron E1505 (which they don't make anymore, from what I know) and I haven't had any problems with the actual laptop, itself. The only negative I've experienced is the fact that my battery started to die only 4-5 months after purchase (I bought it in February of 2007). About a month ago, the battery failed completely and I'm now on life support so to speak, forced to be plugged into an outlet whenever I'm on. If you have a warranty though, the battery is covered, so it's not the end of the world (their batteries are expensive as hell though, if you don't have a warranty). As far as the fans being noisy like lukewarm said, I can hardly ever hear my fan, unless it's midnight, my house's heater is off, and the TV is off, and I'm not playing any music. Fan noise isn't a problem for me. Also, the computer has not slowed down a bit since I got it. Everything else about the laptop has been great. I don't do any video editing, but I do do quite a bit of image editing/designing for my graphic design class on here, using both Photoshop and Illustrator, and I've experienced no problems with running both of them at the same time. These are some of my specs (I don't remember everything) :
Windows Vista Home Premium
Intel Core 2 Duo T5600 (1.83GHz/667MHz FSB/2MB Cache)
2GB Dual Channel DDR2 SDRAM at 667MHz- 2DIMMs
15.4 in display (don't remember the exact specs)
256MB ATI Mobility Radeon X1400 (Video Card)
80GB SATA Hard Drive (5400RPM)
85Whr Lithium Ion Battery (9 cell) (the crap battery)
I don't know exactly what type of programs you would use for video editing seeing as I've never done it, but you'll definitely want at least 2GB of RAM, and will definitely want to avoid an integrated video card. As far as the processor goes, I don't really think you'll need a core 2 quad; that's a bit overkill in my opinion. For the display, I don't know what size you'll want. Go look at some in person to get a feel for screen sizes. My 15.4 inch is fine for me, though I guess it is a little bigger; a 14.1 inch might be good enough, but again, go check some out in person to get a feel for what you like.
As far as companies/brands go, like I said, my dell has been fine for the soon-to-be year I've had it aside from the battery being not so good. My desktop is a dell as well and it was fine up until about a year ago, but by that time it was 6 years old, the hard drive was almost full, and the thing only has 256MB of RAM, so you can't really blame it for going downhill like it did. The only other computer company I've had experience with is HP, which was our desktop before we got the dell. I honestly don't remember a thing about it, it was so long ago, and it probably wouldn't be all that relevant today with the time difference anyway.
And I can't tell you a thing about Mac's aside from the fact that I personally am not a fan of them.