Estimated Delivery Date
We really need for there to be a way that customers can get an estimate as to when their order will be delivered for different shipping options.
This should be based on the time of day and take into account that orders received on weekends or after 1 PM are shipped the next buisiness day - of course, other venders could customize this to meet their own shipping policies.
Customers should be able to figure out when UPS Ground versus Air versus FedEx versus US Mail will deliver their order.

-
Steven Packard commented
I tried to impliment a function to do this in Javascript, but ran into a bunch of problems. This would be better implimented (at least partially) on the server side.
Of course, some of the shipping options are easy: UPS and FedEx overnight will deliver the next day. However, UPS Ground, FedEx Ground and US Priority Mail will take a different number of days depending on the destination zip code. However, it can still be worked out based on the zip code. All these services allow you to do so on their sites.