Going to upgrade Domino/Notes... which version is right for me?

I am going to upgrade our current install of Lotus Domino/Notes this fall. We are currently at 7.0.3 on the server and am using 6.5.4 and 7.0.3 clients. At first, I was leaning towards going with the 8.0.x version, but would like to get on the latest version, 8.5.1 (which, hopefully will be release in October.)

The things that push me towards 8.5.1 are just being on a release newer than what we are currently using and the ID Vault. I know that going to 8.0.x would satisfy my first objective of being on a newer release. The ID Vault, I think, would be a huge improvement over what we are currently doing with IDs, which is next to nothing and scares me greatly.

As far as how we are currently configured... we have two Domino servers (the primary server and a Good Mobile Messaging server.) We have about 120 Notes users, with which about half of them are using Notes through Citrix Xen App servers. We have about 5 or 6 custom apps and one 3rd party app (QSI System from IBS America.) We use Notes primarily for email, calendar and scheduling, and the previously mentioned apps. It is my hope, after upgrading, to bring Quickr in house, and begin promoting its use throughout the organization. I'd also like to see if Traveler would be able to eliminate the cost of the Good Messaging app.

I'm thinking that, since we are a relatively small install of Domino, and since we don't use a whole lot of the other features Domino/Notes has to offer, it wouldn't hurt too much to go to the 8.5.1 version, once it has been released.

We're not a Sametime user, and the likelihood of us going that way are slim and none, so Sametime plays no part in this discussion.