it's a real shame it'll the last season
with that ending to S4, i could envisage that plot running for a lot longer than 16 episodes
sure, long running shows can be a pain (decreasing viewers etc.) and TV is all about the business and money, but Chuck is awesome!
If you want some alternate dramedys to distract your sorrows from Chuck, I recommend USA Network's 'Psych' and 'Burn Notice' (both running to at least a sixth season, S5 of psych has aired, S4 of burn notice has aired) . The burn notice plots aren't as good as the Chuck ones, and Psych is around 95% humor, but they're fun shows