These are my favorite 4.
1) The Colours of Spring by Terry Redlin
When viewed in person this is by far the most amazing painting I have ever seen.
2) Still Life with Gilt Goblet by Willem Claesz Heda
Another painting that in person is amazing.
3) The Garden of Earthly Delights by Hieronymus Bosch
Stared at this one for a long time and before we left went back and looked at it again.
4) Study of Ted Williams by Graig Kreindler
Never seen it in person but in pictures it is my favorite sports painting. The big plus with this one is it is by far the only one I could actually afford to own.