Eagle Creek are supposed to be the best, but there are lots of really inexpensive options on Amazon that work well too. It might be worth at least starting with a cheaper option to see what size combinations work best for you. The combo-size packs aren't always the most useful. For instance, I found I have no use for the large sized cubes—they're just way too big. Three slim cubes are plenty for me for long trips (4+ weeks) in warm weather (similar to these) and two slims are enough for any trips shorter than that. Longer winter trips I use one medium cube + one slim (I need a bit more width for sweaters & heavier fabrics). The mediums are quite large and fit a LOT of clothing though.

There are also compression options too. I've heard great things about Eagle Creek's compression cubes, but I don't use compression cubes so I haven't tried them personally.