Thanks for this site, real awesome, wish every country in the world had such sincere information.
Anyway, I have been in Riga twice, one time for a holiday and the other time for a work trip.
Usually before visiting a country I get the respective Lonely Planet book which I usually find very helpful to help me learn about the city and show me around. But...for Latvia there isn't one dedicated book, the ones that include Latvia also include other Baltic states...mmmm...is it possible that this country doesn't have that much to offer? I beg to differ.
The following I especially enjoyed:
The old city obviously, its a photographer's paradise. While walking around you have to look up too, magnificent building decorations, picturesque streets, and beautiful churches, which are worth a visit too.
The museum of Occupation is something one should not miss, very moving.
The war museum at the Pulvertornis is also worth a visit.
My best experience was however
the National Museum of Art, amazing! Paintings by Janis Rozentals are impressive. While there, a pianist came to rehearse, and later an opera singer joined in, creating a superb atmosphere of music and art! All the art around the city left me with a very good impression of the Latvian people, and really hope more people start appreciating this city....including Lonely Planet

And the girls? Well, that deserves another post!
By the way, what is typical Latvian food, and where can I taste that?