I'd say my typing is pretty "typical" - emails, web browsing, chat, basic MS office docs, etc. I don't type long papers or anything. Is there something much cheaper out there, or are these recommended keyboards worth the money?
Well over here mechanical keyboards are very expensive, two to four times the cost of a good rubber dome keyboard and as such I'd only recommend them to someone in the UK if they're looking for a nice typing keyboard (or they know they like them). Pricing may be different for you though, and if they're relatively or absolutely cheap they may be worth it.
As you're in the US you've got access to a very good second hand keyboard market so if you're interested in trying a mechanical keyboard then I'd pick up a couple of cheap second hand ones first. If you find them too noisy or not suited to what you want then you won't have wasted much money.
Would it be that easy to clean these mechanical switch keyboards? I hate getting gunk in my keyboard.
They're not at all easy to clean. Cherry and Alps switches are both rectangular boxes underneath soldered to a metal plate or circuit board so while you can take the keycaps off and throw them in the dishwasher, you would have to clean the gaps between the switches manually. Fake Alps would probably be the slightly better choice in this regard since the outside is more intricate and less boxy then the cherry ones but they're the sort you probably won't like if you weren't keen on the Dell.
The option not yet mentioned is
(say it quietly) scissor switches that are used on the low-profile laptop style keyboards. These probably best satisfy your listed requirements requiring both little force to press and have very little travel. However, I believe a lot of these aren't easy to clean either as each individual key has stabilisers.
Rubber dome keyboards are probably your best bet on the cleaning front, some of them can be difficult to take apart (I'm currently typing on one where the keyboard is semi-permenently held together with a internal metal case) but others like your dell are very easy and you can chuck all exposed plastics in the washing machine.
I did see this SealShield keyboard, have any of you used it:
http://www.sealshield.com/sealshield.htm
It claims to have "Key Switch Membrane key switch with tactile feedback".
Tactile feedback just means that you can feel something when you press the keys down, it says sod all about what they're like or what sort of mechanism they use.
I'd generally be suspicious about sealed keyboards though since the sealing could have interfered with the feel.
HHKB Pro II is currently "only" 185 euro or 250 dollar.
Plus delivery and whatever it costs to import (18.5% here).
I know you want specific recommendations but I'm afraid I haven't tried enough keyboards currently in production to give you any. The rubber dome-based Cherry Cymotion Expert is supposed to be well-rated around here for a typing keyboard, but I don't know how easy it is to clean or how well it satisfies the rest of your criteria. I've just ordered a new cheap keyboard, but it's not for sale in your country so that's no help either.
Deck Legend/Steel Series 7G/Filco *ML model - These three all use linear cherry MX switches. They're obviously marketed as gaming keyboards but the springs are quite strong so if you're after a feeling of 'fast' keys then these may not be for you.
