Before I get too deep into the weeds, are you looking to play at cap? TR right at 30? At 20?
Broadly speaking, pure monk is solid (and easy to remember) if you plan on playing past 20. If you're TRing at 20 go 18 Monk / 1 Rogue / 1 (Fighter or FvS) because while both Rogue and Monk get +15% attack speed with quarterstaves, Rogues can get it at T1 enhancements and Monk has to wait until capstone
If you're not set on a quarterstaff monk, consider going 18 Alchemist, Wizard or Barbarian. Any of those would pair well with 2 Rogue, or 1 Rogue / 1 Monk (except Barb), or add an FvS level, or a Fighter level, etc.