I'm running Infinity Kappa components. They sound good, especially for the price. I've used Alpine Type-R components, Focals, MB Quartz, and Eclipse in the past. The Infinitys have decent, well rounded midrange and upper mid bass response and crisp highs. Depending on tweeter placement, the highs can get a little tinny if you use the +3db boost on crossover. But if the xover jumper is set to 0db, they sound great. There are more high-end and better sounding speakers out there, but for performance/dollar ratio, the Infinity Kappas are great.
Are you planning to use an amp or just power the speakers with the new HU? Don't forget to take that into consideration when choosing speakers.