If you don't mind the slower processor and the absence of a camera, the original iPad is still available from the Apple store at a $100 discount from its original price:
I agree with this Yahoo article ( http://news.yahoo.com/s/ap/20110310/ap_on_hi_te/us_tec_tablets_ipad_s_price_advantage ) which notes that you can buy a cheaper tablet but it will be pretty shabby, or you can buy a more feature-laden tablet but it will be significantly more expensive.
If you're a pro, I think an iPad is a great way to show off your portfolio to your clients.
If you're not a pro, I think this is a great gift for your spouse (assuming he/she doesn't have one yet) a couple of days before asking him/her for consent to buy a lens or other gear ;) Hey it worked for me -- now you know how I got the Sigma 50-150. >:)