Alot of it will depend on what you're doing in those 10 days off the bike I guess. If you're still going to be fairly active - walking alot, doing any other form of exercise etc - then I wouldn't have thought there would be any noticable difference.
If you are for whatever reason sat down constantly for 10 days, enjoy some "culinary delights" and drink more (Im thinking of my normal holiday here as an example) then I'd guess you may find the legs abit heavier when you get back on, but they'll soon readjust. Cardio fitness in my experience takes a lot longer to start any noticable decline.
Im thinking back to when I used to commute day in day out for years. After a week's holiday where the bike would be well and truely parked, the first run out was abit stiff - no problems with the puff, I just "knew" I hadnt cycled for a week or so. Second time out, back to normality.
Edit: And as you've posted whilst I was typing that; redundant!
