To recommend you places beside Seoul, my favorite is of course my hometown, the East coast. If you have plenty of time it would be worth while enjoying the beautiful blue beaches all along the coast and MOST important, Daegae(snow crab)!! Uljin and Yongduk is especially famous for Daegaes but you can find a cluster of fabulous Daegae houses in Gang-goo. Daegae, at extreme size and taste, costs around 70,000~120,000 won. The highlight of it is gae-jang, which is rice mixed with inside meat, soy sauce, sesame salt, sesame oil and dried seaweed etc in the shell. Oh, and after that comes Daega-tang, which is spicy soup boiled with much seafood including daegae. It's a superb summer treat!
see below pictures ;)
seoul has two 6-star hotels: the W and the park hyatt. both are fabulously swanky but the park hyatt is more centrally located. ditto HKtraveler on the westin and shilla hotel.
the traditional high-end meal in korea is royal court cuisine: a set menu of what seems like an endless procession of little dishes. my fave is "durae" in insa-dong. (see attached photo)
also be sure to try grilled han-oo, the local korean beef that is outrageously expensive but worth every penny (or won).
re: steve h.
But to travel all the way to Korea for French food? The Ninth Gate is OK and a good stand-by if one is craving French food. But it certainly isn't worth the trip. The Westin hotel is nice though. If you are here for business and you want to be on this side of the river, this is the place to stay for convenience. If you don't mind a bit of distance but want a more tranquil setting, go for the Shilla.
As for food, best high-end grill beef place is Bamboo House. Can't go wrong with it. Try the various different cut of beef. Think my favourite was An-chang-sal or dong-sim.