Eclipse Juno Perspective tool bar

There is actually no need to reset your perspective, let alone to nuke your workbench.xmi memo file. There is a smarter way:

1. Open a new workbench window. From the main menu: Window => Ǹew Window. Please note that the new window does have the (already customized) Perspective Bar.

2. Close the window that does not have the Perspective Bar first.

3. Close the second window. This will save a cleaner version of workbench.xmi (overriding the one that has a perspective bar positioned out of the screen).

4. Reopen eclipse. The Perspective Bar is back at its place.

There are two things you can try:

1. Reset your current perspective (Window/Reset perspective...). Although your configured set of views will get lost, it might bring back the perspective switcher.
2. If that does not work, then you should reset the entire saved workbench GUI. This can be done by deleting the .metadata/.plugins/org.eclipse.e4.workbench/workbench.xmi file from your workspace folder, or by starting eclipse with the -clearPersistedState

Point 2. assumes, that in case of Juno you are using Eclipse 4.2 (the new GUI, not 3.8, the old).