Sigh. The server will be 1.5 when a CraftBukkit build which is stable enough for plugins to update with, is 1.5.
We run CraftBukkit, which is a modified version of the Mojang Minecraft_server.jar
So it doesn't update when Mojang does. It relies on Mojang.
A recent announcement from the Bukkitdev team said that they expect a lot of "bug fix" releases from Mojang (1.5.1, 1.5.2, etc) and they are waiting until Mojang is stable until they begin to update their modified version. So it will be that much longer.
AFTER the bukkitdev team updates the modified server jar, THEN all the plugins which use it have to update to agree with the new version. Many of them have no choice but to update because they use NMS, which recently became version specific in the Bukkit code. Very few are stable enough to stay unbroken.
After we have versions of plugins that we can rely on not to crash and burn, THEN we will update.
Tl;dr? Learn to downgrade, it's a valuable tool regardless.