Giftcertificates.com now charges a service fee for emailable GCs (even Supercertificates). At 95¢ per GC, it may not be worth the cost.
For instance, CR offers 5 points per $spent. A $50
Amazon GC will get you 250 points. It costs 2,100 points for $10 Disney Dollars or 210 points per $received. Since you will have spent almost a dollar to get those points, you will have basically netted 40 points for your $50 spent. That's not a very good return for your bucks. Of course, if you're going to order $100 Gcs or higher, there is a little better return for your $ but not much.
I would look into other online merchants who offer the same items for similar costs. Barnes&Noble has books, cds and dvds. Walmart.com has similar offers to Amazon's Target.com. Look to Bestbuy.com, Circuitcity.com and Compusa.com for computers and electronics. KBToys.com has pretty much the same selection as Toysrus.com and they do refunds and exchanges right at their B&M stores.
If you are absolutely devoted to shopping at Amazon.com, the following programs reward directly for purchases with them:
MilesMall 1pt/$3
WePaid 2.5%
I don't do either of those programs, so I cannot tell you how good they are at crediting or sending rewards.