Hip Hop is almost always in 4/4, and it does have a pronounced swing.
Here's the description from Wikipedia:
"At its rhythmic core, hip hop swings. Instead of a straight 4/4 count (pop music; rock 'n' roll; etc.), hip hop is based on a triplet feel somewhat similar to the "swing" emphasis found in jazz beats. Hip hop takes this concept a step further, however. Whereas jazz swing implies three eighth notes (a triplet) per beat, hip hop implies six sixteenth notes (a "double triplet") per beat. Like the triplet emphasis in swing, hip hop's double triplet "bubble" is subtle, rarely written as it sounds (4/4 basic; the drummer adds the hip hop interpretation) and is often played in an almost "late" or laid back way."
I think the difference is that jazz and blues use one triplet per beat (3 8th notes), hip hop uses 2 16th note triplets per beat. I think the 16th notes come across as slightly more straight, which is why some were under the impression that hip hop is just straight 8s.
Although most hip hop is going to be in 4 (backbeat on 2 and 4). There are some newer examples of hip-hop using different time signatures (3/4, 7/4), as more experimental types of hip hop are coming out.