These days I'm running bike-heavy White Scars lists. Here's a modular list; at each points level (1000-1500-1750-2000), I simply add more stuff. It's not meant to be tailored for any particular opponent or tournament, but I found that this kind of list excels against
MEQs and other armies with low model counts.
I'm always using the good old Combined Arms detachment. From 1500 points and up, I'm running two such detachments. No formations. With Kor'sarro on a bike, I can make my bikers scout. I favor Divination for my librarians, since it's versatile and I like re-rolls to hit for my plasma guns. Plus, Scrier's Gaze is useful for my reserves.
1000
Librarian on a bike, level 2 [110]
Command squad on bikes with 5 flamers [150]
4-man bike squad with 2 plasma guns [114]
4-man bike squad with 2 plasma guns [114]
4-man bike squad with 2 plasma guns [114]
4-man bike squad with 2 plasma guns [114]
2 attack bikes with multi-melta [100]
Attack bike with multi-melta [50]
Stormtalon with typhoon missile launcher [130]
1500
Kor’sarro Khan on a bike [150]
4-man bike squad with 2 plasma guns [114]
4-man bike squad with 2 melta guns [104]
Stormtalon with typhoon missile launcher [130]
1750
Librarian on a bike, level 2 [110]
Stormhawk with skyhammer [130]
2000
7-man Honour Guard with chapter banner and drop pod [260]