My teacher just started me on the Four Star series.
I second the use of Four Star. I used the series for about a year until it became too tough! (I might get back to it at some point)
I started on level 2 and worked up to level 4 until it got crazy. Started from the beginning again, and again, a couple of times adding a level to the rotation.
I quit at level 6 when I found it ridiculously hard for me - the series is certainly challenging, but effective. It ramps up quickly when you least expect it.
I haven't now for a long time had to write the note names individually above each note, and can sort of sight read / keep up with my oldest kid's weekly assignments. I know I would be completely lost had I not pursued remedial sight reading with the Four Star series.
It's not that it's necessary, but it sure helps.