The tentative blueprints for what is to be talked about at the development summit for Ubuntu 11.04 is laid out on Launchpad. Some of the tracks that interest us for this Natty Narwhal summit are listed below.
Btrfs support: Canonical has had plans for deploying the Btrfs file-system and with Ubuntu 10.10 there is support for installing to a Btrfs root file-system. It was even considered at one point that Btrfs could be the default Ubuntu 10.10 file-system, but that didn't happen with the trusted EXT4 still being used. It's a possibility that Ubuntu 11.04 may use Btrfs as the default file-system, but that still may be a stretch, but it will be interesting to see what plans the developers have for this next-generation file-system that supports. Btrfs supports features like disk compression, SSD optimizations, and via sub-volumes and snapshots it can do things like system rollback support and find regressions really fast.
Multi-Touch Support: Canonical is very interested in bettering the state of multi-touch support and gestures in Ubuntu and Linux. While there's been Multi-Pointer X in the mainline X.Org Server for a while now, Canonical has been working on the X Gesture Extension, it's own multi-touch framework, and making Ubuntu applications more multi-touch aware and compatible. With Ubuntu 11.04 the multi-touch and gestures support should continue to build upon the foundations found in Ubuntu 10.10.
Ubuntu Software Center: Originally known as the Ubuntu Software Store, this package manager that was originally introduced in Ubuntu 9.10 has been refined in Ubuntu 10.04 LTS and Ubuntu 10.10. With Ubuntu 11.04 there will be more improvements. There are tracks at UDS-N for talking about ratings and reviews within the Ubuntu Software Center and possibly switching to PackageKit rather than aptdaemon as the center's package back-end.
At the moment there's a total of 61 blueprints to be found on Launchpad for this next development summit. UDS-N is taking place later this month in Orlando, Florida.