This Greasemonkey script takes a list of "Albums of the Year" albums - e.g. this one - and looks each up in the Spotify Metadata API, adding an icon and link if the album is available in Spotify: spotify_album_lookup.user.js
Note that it doesn't have a territory selector yet, so some albums marked as available in Spotify might not actually be playable in your area.
"Albums of the Year" pages are also Playdar-enabled now. With Playdar running locally, a first click on the Playdar icon next to each album will look up the track titles for that album in MusicBrainz, and a click on a track title will search for that track through Playdar, starting playback immediately if it's available.
Update: I've integrated Spotify lookup into the site now, so the Greasemonkey script isn't needed (unless you want to trigger the Spotify lookup automatically when pages are loaded).