Alan Dunlop, well i think that Lisbon would be a good choice for your office trip next year because you can find in an old city great buildings or urban plans from the XIV cent. to now days. The downtown was re-builted after the earthquake in 1755 and it stills a great urban concept. Instead of what happend in Sevilha, the Expo 98 in Lisbon was part of a urban plan that considered the future (after Expo 98) that was designed and builded very fast. Even then the result is a very nice area near the river that includes great buildings from "good" architects, plazas, equipments, urban furniture and also nice pubs (or cafÃ©s as we call it)
. For exemple Siza and Calatrava buildings dist from eachother only about 200m!
You can also easly find good architecture guides of Lisbon. But Portugal is a small country, wich means you can also travel around. At the South you will find the tradicional Alentejo houses (only possible with this climate) and at the North you can visit Oporto (a large concentration of SizaÂ´s buildings!).
If you consider to visit Lisbon i can help you with some portuguese architectures websites where you can find more information.
To visit Expo 98 trough the net go to : http://www.parquedasnacoes.pt/
its not very good (mainly text) but it will give you an idea.
About the RIAI convention in Lisbon i have no idea if there will be one.