I'd go with the Desktop and PDA solution--err option. (I've been looking too long at webhosts...)

Here's why:
PDA's you can take with you all the time, and are very, very handy. Laptops you only take with you when you know you'll need it, and you're not going to use it to jot down notes.

Desktops are far cheaper and easier to upgrade and tinker with. If you'll have time, they also are certainly better for games.

lets make one thing clear, laptops are NOT underpowered anymore

desktop replacement systems are just as fast as dekstops and have no problems with any kind of 3d games. I own such a system I bought one and a half year ago and still have no problems with any game at all.

Another pro is that since you cannot very easily upgrade laptops (actually I can even upgrade my cpu, but very useless...) so you'll be spending less money afterwards. Sometimes there are great deals, I got my rig for €700 for example and even have a dvd-rw in it.

Meny users write about 'upgrades' as a con for laptops... Of course - you can't upgrade a laptop, but why would one need that? Let's say you buy a laptop now. You'll probably get a 3.0 MHz processor, but one with a good graphic card, and that's all! If you'll need a larger HDD you can change it to a bigger one! If you'll need a larger amount of RAM, you can get more! And you probably won't need a faster processor for let's say 3 years from now, and the graphic card should hold for even longer!
There is one thing that can break everything that i've said. If you need the computer mostly for gaming - a desktop would be a better choice. But if you work on it as much as play - choose laptop! I'm working on mine, and i play on it casualy. It's an old model, but still i find it good for games!
It's all up to your needs.

This is such a hard choice... I don't think either choice is optimal. I went to a wireless-enabled college, and I found this solution optimal: get a desktop and a laptop! Just get an old or used laptop that you can work on but not play on... since you have wireless access, your laptop can always "call home" to the desktop, letting you use the desktop as the real workhorse. Gaming on desktops is always better than on laptops anyway. The laptop won't wear out as fast cause you'll only use it when you're "out". For the cost of a good PDA you can get a laptop that's a few years old... maybe as fast as 1 Gigahertz, with a basic graphics card and wireless access. Use the laptop as a portable connection to your desktop, and you're all set!

I would go for laptop, i'm using a laptop all the time (for everything) and it's just cool.
it's small, the batterys are pretty good (it can just keep on like 4 to 5 hours a day, using it alot. the screen is better, the keyboard is better.
i can't upgrade it, but that doesn't matter, it works like this (pentium 4, 1.8 GHZ, 30 GB hard disc, 15,1" screen, toshiba pro 2100 i think) i can play most games on it, and it's 3 years old now!
i can take it anywhere, and at home i use a mouse with a wire on it (USB)
and if you look at the pricing, for about $800 to $1,500 you have a good laptop (thisone was more expensive, because of the bigger screen <extra large because i don't have very good eyes>)

well, I would actually go for a laptop, but it is more towards preference and situation than either/or. For me, my current computer works fine. It is getting a bit old, but it has Panther, nice apps, and it gets my homework done and allows me to talk to my friends, etc. So, going on to college not only are new computers incredibly nice, but by getting a laptop you not only succeed for yourself an utterly new computer, but it's also portable and, in terms of at least mac powerbooks and ibooks, completely wireless ready.

and hey, laptops are cool.

The Major point for me is price.
You simply get more for your money with a desktop
Desktops are better if ya like to tinker with it all.
i'm sort of biased anyways, since i don't tend to like working on a laptop. I prfer having a system on a desktop all spread out so i have space, not having the screen and key board a few CMs away frome each other. I'don't like being confinded
But thats jsut a personel preference.

Although if i had a ton of money i mite go for a laptop.

one thing has come to mind though, yes, you can get some pretty high-end tech for lap tops, but do the cooling systems cope well? (a question not a dig )

it gets a bit *hot* after a whole day of activity (playing games, using microsoft office alot, browsing websites, downloading/uploading stuff, opening books for school in adobe reader etc) but it can work between the -50° and +50° C so i'm safe i guess....
this laptop is 3 years old now, and still working fine, i can still play NFSU2 on it

I would only get a desktop if you like to mess around with the insides and customize things. Otherwise, laptop, definitely. (Try to get a 'gaming' laptop.) For all the reasons that everyone has said. Besides, personally, I think PDAs are hard to get used to. My only experience with that... interface is at the store though. And my Wacom tablet, if you count that pen. And well, I don't know much about PDAs, but don't a lot of sites show up weird/not at all?