>>44551466HGSS Heracross is pretty good. About what you'd expect from a Pokemon that has base 125 Attack, a 75 BP STAB before level 20, and can be picked up around the 2nd gym. Kinda takes a bit of work to find but it's worth it.
Scolipede is also worthwhile for a casual BW playthrough. Good enough stats with good enough moves makes it positively good enough.
HA Durant is extremely useful for easy BP grinding in Gens V, VI, and VII.
The problem with Bugs is that most of the ones you get early are dogshit, with most quality Bugs being out of reach until too late in the game to be worth using, or requiring a trade to reach their full potential.
