I adored Krabi - it is stunning, the main resort area is Aonang which is a lovely town - the shoping is great and there are lots of restaurants, beach is not great though but you can take a long tail boat to Railey beach etc - absolutely beautiful.
Plenty of places offer elephant trekking in the surrounding jungle - krabi is great I would definately give it a go, shirleyV

some info hereand here. Krabi is def. on our list of must dos!

Not sure if you're aware that Krabi is on the mainland, it's not an island. You can travel to other beach (and small islands) from both Ao Nang and Krabi. There probably won't be enough shops to keep you happy in Ao Nang but there are more plus markets in Krabi which is only about 25 mins away by songthaew. Other than that why not add a few days in Bangkok for shopping>

Krabi is stunning, but to get to the best beaches you may need to do a few boat trips. Tubkaak beach on the mainland is pretty good but the setting is remote so would mean a trip to Ao Nang for shopping and the like, Khlong Muang a little livlier with a handful of local restaurants and a few shops and I would not call the beach fab...again you would have to hit Ao Nang (20 mins drive away) if you want to be in a lively resort setting.

As Chris12 says try Bangkok if you want to do some serious shopping. An alternative might be to consider Phuket which has very good beaches and shopping choices, although some parts of Phuket are very developed. Elephant trekking is available in Krabi and Phuket (and any other tourist area in Thailand for that matter).

Thank you very much for your replies, all the areas of Thailand look beautiful, that is why it is difficult to choose which area. Bangkok is a must, and we will be spending a few days there.