I'm not an expert, and am making this up as I go along but:

If you have blank CDs to waste, you can try a few Live Cds. And after that it only takes about 20 mins to install and run Linux, an extra 10 for your first time maybe, and then everything works (but if you get sidetracked you can spend hours tweaking the theme).

Running both GTK and Qt applications at the same time is the easiest way to bloat your system. I believe this is the main reason mainstream users care about which desktop they use. Alternative desktop environments such as Xfce generally use GTK, but not nearly as heavily as Gnome. Personally I think Gnome and KDE are too bloated to have lots of fun with on a laptop and therefore recommend an alternative. I like the open design of Gnome but had a couple problems getting little things to "just work" so switched to KDE, which worked great until I was driven insane by bloat. The desktop environment I use now is called Openbox (via Crunchbang Linux) because I like the name Openbox =P

I'll use this paragraph to ramble about some run-off things: the reason I'm using an Ubuntu derivative is because they have a ton of applications in their repository (based from Debian) *and* if anything comes up I can usually find an easy to read tutorial on the Ubuntu forums (especially for my old N50 gamepad). Derivatives are important because of the install package file they use: Debian uses .deb, some others use .rpm or something else, and the main benefit of Slackware (the oldest surviving distro) is they use the source files. I believe in the past .rpms especially were really bad with dependencies (so if you installed applications in the wrong order, things would break); I believe the gap is almost closed now, but by design Slackware still holds an advantage? And Slackware is good if you're smart and decide to learn the boring technical details without having your hand held, but you can accomplish this on any distro today.
Edit: I've never used Slackware directly, and just looked it up and looks like they've made recent changes, so pretty much everything i said there is wrong =P

Firefox 3 seems painfully slow and buggy on Linux (I'm using the standard that anything not five times faster than Windows is painfully slow), but I believe Firefox is still number one and recommend it to all. Epiphany and Konqueror are reasonable Gnome/KDE browsers, Opera is an alternative the same way it is on Windows, Google Chrome seems to have potential, and there are exceptional text browsers out there.

For a new user compiling a package just means downloading it from some random website, unzipping it, then typing "./configure" then "make" then "make install" in the terminal, all while praying you have the dependencies and that it actually works. This process requires you to have a couple applications enabled, and it's bizarre that Ubuntu doesn't include them by default, but you'll be reminded to download them once and then you'll be set.

I think Fedora has history and targets a different userbase, I've never really seen it recommended to new home users. I tried MEPIS and Mandriva a couple years ago and had a good experience, only naming them because they're pretty big and user-friendly and haven't seen them mentioned here. If you're considering Gentoo in the future I also recommend taking a look at Arch (and of course if you want a Gentoo derivative the already mentioned Sabayon is excellent).

Overall, I'd recommend trying an Xfce distro (Xfce distros generally target new users who want something slightly faster than KDE/Gnome), then dual boot with Linux Mint if you have enough space for all those plus Win XP, then delete the one you don't like and you pick something. You need about 5-20gb for each "/" root partition, and hopefully you figure out how to make a separate "/home" home partition so that you don't lose your personal files if you try a different distro.

Good luck, if any problems come up there *is* a "simple" fix for it, but might be hard for a new Linux user to find since they're not used to it.

Can't remember if anyone answered drivers, but any that you need shall be in the repository, you don't have to look for them. The closest example to an exception is say if your videocard/chipset is Nvidia you might have to install a certain nvidia driver from the repository. With Ubuntu I go to System tools and use the "Restricted Device Manager" for that, but I forget why.