Playstation Plus has always been a highly attractive option for those able to join in, and the Instant Game Collection has only improved the package, with select games available as free downloads for limited periods. Though these downloads would no longer be yours if you left the service, they're free, so who's complaining.
As a heads up for tomorrow's update, Sony has confirmed that PAL members can look forward to Lara Croft and the Guardian of Light and Saints Row 2, so no-one can complain about a lack of diversity. You'll also have the opportunity to download the various DLC extras for each title at 50% off for the next two weeks, resulting in a lot of gaming for relatively little buck.
If you fancy isometric co-op action or sandbox insanity, then you're pretty well covered. The next big update to the Instant Game Collection will be on 1st August, when Deus Ex: Human Revolution will drop out.