HIV and AIDS - The Body
This is a world class HIV and AIDS information resource, with in depth insight from many experts.
Mental Health Help
This site offers an award-winning guide to many different mental health conditions.
This site edited by a Canadian psychiatrist is an excellent starting point for more detailed reading on a wide variety of mental health issues.
The British Medical Journal
Although aimed at doctors, this is a fantastic resource that patients may find very useful for more in depth reading. There is a powerful search facility which will search the journal back to 1994. Entering the condition in the "title" search box will usually produce an editorial or good review article. Tell your doctor about it if they have not heard already!
Travel - The Centre for Disease Control
This is an excellent site by The Centre for Disease Control - check out the areas you are travelling to under "destinations". This provides detailed overviews of recommended vaccinations and malaria prevention.