Some of the most stunning beaches are situated on the Northern Lakeshore. Ngala, Makuzi and Nkwazi all offer excellent camping facilities and are beautiful spots. If you're looking to spend Christmas somewhere then try Ngala, they always lay on an excellent spread -
ngala@malawi.net or 002651295359.
Elsewhere in the country, Mulanje and Zomba are gorgeous areas for climbing and hiking. Both have some decent campsites and offer the best views in all of Malawi.
Hope that's of some use,