Well when it comes to a Motherboard we need to know these following things to help you.
1.Which CPU manfacturer are you going with. Intel or AMD ?
2.What type of an Intel or AMD system are you going with. Intel ( 478,LGA775 ) Or AMD ( 939,AM2 ).
3.Are you going AGP or PCI-E.
Unfortunately you cant really get a motherboard that is waterproof/Condensation proof as of yet without somekind of treatment such as Dioelectric grease.
When it comes to a Graphics card once again it depends on if your motherboard will be AGP or PCI-E..These are things we all need to know.
However a Cheap G-card for :
AGP : X1600PRO
PCI-E : X1600XT Or X1800