Basic construction for me. Taking 2D drawings and turning them into a hull and superstructure with the correct lines is what floats my boat, everything that comes after makes me think I'm building a doll's house (especially doing the interiors).
Regarding what types, post 1935 small service craft every time. CMBs, MTBs, MGBs, SGBs, MASBs, MLs, HDMLs, FMBs, HSLs, RTTLs, STs, RSLs, GSPs, FLs, RCLs, GSLs, HSTTLs, whichever of the three services you pick, they all had fine looking small service craft.
Oh, er, sorry, warship I guess, followed by yacht.