I'm wordy, I needed a whole other post for this
I personally do not care much about show gardens unless they feature a lot of herbs or some vegetables. As I'm only 5ft 2inches tall, I'm usually completely unable to see the showgardens anyway as there's a crowd of giants in front of me usually and even when I do get to the front, it's not exactly a good view of the garden. It's not likely that I'll have the money or willpower to ever build anything like a show garden in my own home if I was able to (live in rented accom and only have the allotment otherwise).
I usually only go for shopping purposes
There are lots of stands selling all sorts of garden sundries from the useful to the pointless. There were a lot more botanic art sellers at Chelsea than at Hampton Court Palace I noticed. Sutton Seeds and Thompson and Morgan both had seed stands. Sutton Seeds had a bargain bin of beet and spring onion seed "tapes" for 50p so I have some spring onion tape to try out sometime when I can find the space and time to plant it.
In the pavillion, most of the show stands sell seeds. I purchased cacti/succulent seeds, carnivorous plant seed and herb seed from various venders in the pavillion. There were two stands featuring only herbs (Jekka's Herb farm and the cottage herbery i think was the other) and a few exhibits used vegetables as part of their decoration, the farmer's union (?) was one and the
bournemouth council display was another. A lot of the show gardens have chosen to use Angelica plants in full bloom as an arcitectural plant which was quite interesting to me since my angelica plants are about 6 inches high. I talked to Jekka herself briefly about them and she said they only get very tall like that in their second or third year of growth and this year my plants would only grow wider not taller.
There's also various educational stands there. I think the fungi society were there (well it was something to do with fungi. Did you know that yeast is a fungus? I didn't know it was classified as such!) and the royal society of pathologists were there, promoting their work with various plants for their anti-cancer properties. The eden project was there with their brassica information stand which was quite good as well.
I'd still recommend Hampton Court Flower Show over Chelsea. Chelsea just heaves with people and yet it lacks a lot of the stuff they can put out near Hampton Court. Hampton Court has a lot more stands selling plants and generally more sundries. Hampton Court has more than one pavillion and they have a grow and show fruit and veg pavillion which is quite interesting. There's more information stands about various societies. In summary, save your money and go to Hampton Court Flower Show in early July and go for the whole day. We only just managed to do all of Chelsea with our 3pm-8pm tickets.
More photos which I've not got around to captioning:
http://www.stargazy.org/chelsea2006/ The very exotic brightly coloured display is the south african stand, I think... I still love those bright pink pineapples!