Following the release of DebianSarge, the current DebianStable distribution was released on 2007-04-08 under the codename Etch.
The new features are in ["NewInEtch"].
A summary of the initally planned features, as discussed on debian-devel, went to ["EtchTODOList"].
See also:
DebianSarge (the release preceding Etch)
DebianUnstable (code name DebianSid)
For upgrades, see Sarge2EtchUpgrade.