Don't get me wrong, I love Kea, Poros (at anchor) and Dhokos. Even though it's madness/manic I think everyone should go to Hydra at least once too.
To add to your list, I like Ak Sounion, just around he corner from Lavrion; though again you need light weather
as any swell soon works in there and the holding's not the best. Methana (doesn't smell as badly as reported), Vathi (small, so avoid weekends) Epidhavrous and Aegena (Very busy weekends and Thursdays too) in the Saronic. Just outside there's Ermioni (don't anchor - you'll roll all night) just N of Dhokos and Porto Khelli across from Spetsai. We like Astrous & Navplion too, though they're quite a haul with only a week from Lavrion.
Also the western Cyclades
going south from Kea - Kithnos, Siros and Serifos (our favourite) are lovely, though don't head
too far east/south and watch the weather, as it can be a wicked windward beat back up to Lavrion if a Meltemi sets in.
Just go where the wind
suits best and enjoy.