i'd get the vacanze print if you really liked it. for me, i found the print to be a little too winter/christmas specific, so i decided not to get a bag. i did however like certain characters and purchased a denaro with them on it instead (it'll have moofia, the eskimo and the penguins on it). i'll use it for the winter time.
i like to switch bags all the time, and i find that with the tokidoki purses, i tend to wear them according to the seasons.. like my favorite print is the OP which i wear in the summer. i've been sporting my inferno lately since it was halloween/fall time.
I don't think that Vacanze is any more seasonal than Spiaggia. I'm sure people still use their Spiaggia bags when it's not beach weather any more, so why not use Vacanze whenever you feel like it too? I love the Vacanze print and I plan to use it year-round.
I do feel that Vacanze is very seasonal...not even just winter...but just for the holidays with the christmas trees. I got a small bag and it has a lot of white stuff on it...I haven't used it yet...hope to but we'll see. Mind you, I do use my Spiaggia now...and it's 30 degrees and snowing out.