I use the FREDRIK desk from IKEA. It is adjustable, it is a standing desk, and does not look like it should fall apart anytime soon - what more could you ask for?
I switched to a FREDRIK after the previous HN discussion on standing desks. In general, I am quite happy with it, but some notes from my experience:
You cannot adjust the height of the shelves without taking most of the desk apart. The increments are fairly course, so it may be difficult to get the height right -- I had to dig up the riser which came with my Microsoft Natural keyboard.
I use it with an IKEA bar stool and often switch between sitting and standing a few times during the day.
I will second this. Make sure you're looking at the $150 Fredrik "Computer work station", not the $100 Fredrik "Desk". The Fredrik has extremely solid steel support. I've used it for over a year and a half, most of that time as a standing desk, and have disassembled and reassembled it at least a half-dozen times (for height-adjustment of the desk or shelves or for moving). It holds the weight of a 24" iMac, a second display, a stereo receiver, and two shelf-lengths of books with no bending or bowing whatsoever. I even have a habit of leaning on it when I'm not typing, and it's held up to it perfectly.
That looks very interesting (particularly as it's a desk which is widely available across countries) but 98cm max-height seems a little short for a 6' 2" guy like me? I'm assuming that you elbows should still be at right angles (i.e., that the same rules apply whether sitting or standing)
I bought a GeekDesk a month ago and I love it. Typing from it right now. It's big and sturdy, fully adjustable. Can't go wrong with it. http://www.geekdesk.com/
FWIW, I personally got myself a basic ELFA set http://www.containerstore.com/shop/elfa/bestSellingSolutions... . Cost me $350 down here in australia with a simple two desk setup. Also had to go through the hassle of getting a handyman to set it up, and then a comfy bar stool for switching between sitting and standing.
Closer to $500, and not as much surface area as a regular desk, but great Swedish quality and definitely a relief for my back.