Just out of curiosity, would most nonprofits really need a gigabit switch? If Cisco's willing to donate them at a reasonable price, I would say full steam ahead, but I don't really think that many nonprofits are pushing enough data around to warrant paying more for gigabit. If we're looking for more midrange switches, I'm a staunch supporter of the Catalyst 2960 series; I've always had great success with them, and to date have never had one fail (I have had Dell and Netgear switches fail on me, but not any 2960s yet! Fingers crossed...)
My two cents, anyway. Gigabit would be great as a forward-looking options, but if it will drive up the price to unreasonable limits for nonprofits I think 2960 models would suit us just fine!