Hey I said ebay
My needs are probably a bit different from most; I regularly am out of town for a week or two on business, and I absolutely have to have a notebook that can get my work done onsite while I am away. I use a lot of fairly specialized software, and have about 5 years of research data that I regularly access when working at labs in the US. I am not willing to lug a big heavy bag through airports, and I am perfectly willing to spend the money for a light and powerful solution. I don't know if you ever rent cars, but having a cd burner on notebook is SOO handy when you luck out and get a car with a cd player. As a "satellite" computer tho just for occasional trips I agree it isnt necessary. Many notebooks come with them standard now tho so no big deal. I was never a notebook person until I got this T30, but I am amazed at how nice it is. I am buying notebooks for all grad students instead of desktops as well; I just don't see the point in elaborate data backup and synching when a good notebook can handle all the workload needs.
FWIW, I dont know many younger scientists who bought desktops when they started out as professors. Everyone travels too much, works from home too often, and is too scatter-brained to manage a desktop at home, a desktop at work, and a low end notebook for travel. Why bother when a $2000 notebook can do it all?