Adobe have decided to change the way they release products. Historically they operated a system of 18 months between major releases of the Creative Suite products but have now decided to change this to 24 months with a minor 0.5 release every 12 months.
Its all part of a plan to extract more money of course and Adobe have also decided to offer the option of a software rental scheme at the same time that enables you to pay for products on a monthly basis (no pay – no work).
There is no change to Photoshop software compared to 5.0 so no real reason to upgrade at present though the default Photoshop included in Suites is now the extended rather than the standard version which will be useful when CS6 is released in 12 months time (Update : Applies to the subscription version of the premium only – dash!)
Adobe had better get their pricing right on this, they have a reputation for being expensive, if they push too hard then it will be worthwhile for another developer to challenge Adobes monopoly. I’m not keen on monopolies and Adobe have a real monopoly on image editing software.