Verizon only has one WM Smartphone and it's the Motorola Q. Although you cannot edit MS Office documents on the Q, you can view them. It appears there is some implementation of the Picsel browser (not sure), but you can open a .doc or .xls file attached to an email, for viewing. No WiFi, so you will need a data package. There are voice/data bundles available now that include a somewhat reduced price on data.
There is only one VZW device I know of that has WiFi and it's the Samsung i730. This is a Pocket PC device, so you can edit Office documents as well as view them. This is an awesome device if you don't mind a little extra bulk. The WiFi is a little quirky, but it usually works very well.
As for one-handed use, the Q will be a better choice. If you need to keep track of your calendar, contacts, tasks, email and occasional viewing of documents, the Q is sufficient.
If you need WiFi and have to edit Office documents, your only real choice is the i730. However, you'll need the other hand occasionally.
Both are very nice devices--go to a VZW store and play around with them and you'll probably fall in love with both.
