Concierge class is not necessarily a suite. On our last Celebrity Cruise (Infinity, Feburary 2006), we had a standard balcony cabin, and our cousins had a concierge class balcony cabin. Their cabin was slightly larger, but was not a suite by any means. They also were invited to a few private events (such as a "CC tea"), received canapes in their cabin before dinner every evening, and had a more extensive room service menu than we did. They also joked about how their towels would be a new color every day (as theirs were changed daily, whether used or not). I believe they also received two credits toward Captain's Club instead of one.
On Century, the Concierge Class is a balcony stateroom, 175 square feet interior, 42 square foot balcony. The Deluxe Ocean View with Verandah category -- which is not concierge class -- is 170 square feet interior, 42 square foot balcony.
There's a full list of benefits on the Celebrity Web site -- go to Ships, then Century, then Century Staterooms, and click on the Concierge Class photo.
When is your cruise? We'll be onboard in July.