OSHA website, it's not the prettiest thing in the world but it's chock full of rich information (the broccoli of government-run safety websites!). We're using their checklists for building our new home office and have found them invaluable in making informed choices.
There's a bazillion (note: approximate) task chairs, desks and ergonomic office equipment out there, and plenty of copy cats of the big boys but other than promotional materials you don't really have much to go by. Sure you could sit in them in the show room, but unless it's designed so badly that you feel immediate pain (we're looking at you Office Max Task Chairs) you won't get to see what it's like when you've dug in like the allies at Normandy against your Nazi to-do list. Even chairs featured in MOMA have their downsides. The Aeron has a few detractors.
The OSHA checklists are your ergonomic salvation. First, the computer workstations checklist has specifics on how your body should be positioned while working. Your eyes should be looking forward rather than down (so elevate your laptop or get a monitor), trunk should be vertical and most everything should be relaxed with no strain. This checklist is good for getting things set up in the office, and is less focused on the products themselves. We've implemented them and greatly improved our work environment without buying anything new. We built a cheap laptop stand, put a small pillow in our lower back and stopped working in bed. Stuff you've got around the house is usually enough to get you moving in the right direction.
If you've got the space and you're ready to take the leap into getting products to create or improve your office the product guide will make going to the store or shopping online a whole lot simpler and more effective. Things we didn't think about before like depth and width of keyboard tray or the minimum range for seat height are there and often measured specifically. We recommend printing out the checklist and taking it with you to your local office furniture purveyor. And that's really one of only things not mentioned on the list: that even if everything is going to suit you ergonomically, it won't necessarily suit you visually, stimulate creativity or desire to work, or make you feel good when using it. Going to try things out, checklist in hand, is the way to go. If you're still not convinced of the need for a specialized workspace, perhaps this video will change your mind.