iTunes Smart Playlist combining 2 genres
In each Smart Playlist, you can change "Match ALL of the following rules" to "Match ANY"" to tell iTunes to do a OR instead of AND between elements you specify:
Match ANY of the following:
Genre > contains > Hip-Hop
OR
Genre > contains > Rap
Unfortunately you can't mix OR and ANDs in the same playlist, it's all or nothing. For example you cannot do the following since any song rated 4 or more -no matter the genre!- will be included:
Match ANY of the following:
Rating > greater than or equal > 4 stars
OR
Genre > contains > Hip-Hop
OR
Genre > contains > Rap
Multiple Smart Playlists
To solve this problem, you can create and combine multiple smart playlists that focus on one thing. For example:
Smart Playlist 1: 4+ stars ratings
Match ALL or ANY of the following:
Rating > greater than or equal > 4 stars
Smart Playlist 2: Hip-hop & Rap
Match ANY of the following:
Genre > contains > Hip-Hop
OR
Genre > contains > Rap
Smart Playlist 3: 4+ rated Hip-hop & Rap (if you want to sync to your device, just sync this one)
Match ALL of the following:
Playlist > is > Hip-hop & Rap
AND
Playlist > is > 4+ stars ratings