I'd also recommend Q & A between Resistance and Before Dishonor. While it is disconnected from the Borg story it does introduce one recurring and one new regular (or recurring we don't know how long the character will be around yet) character. It's also a really fun Q adventure that ties most of his appearances together into one big story.
. Q&A is a fantastic book. A quick read and it's not tied down by all the Borg stuff that happens around it . KRAD did a great job on that one