Heh...can't say I know many Dutch subtitled games...and exactly zero where there was a voice sync. The first thing I do, as well as pretty much everyone, is change the language to English. Heck...I doubt even Dutch game makers bother with anything other than English.
Mostly, I'm kinda doubtful to what degree Dutch subtitled games will be helpful in learning the language. It's used less than in a series or movie, and often not of great quality. I feel I should point out the Dutch wii menu here. The Dutch word for "ok" is either "ok" or "oké", with the latter one...seriously outdated (it's how you pronounce it...but nobody writes it like that anymore). Nonetheless, wii menu questions always want you to click "oké".
So yeah...I would also suggest watching movies or series if you want to learn the language. For the movies, you can probably find English subtitles which really help (depends on your current skill, of course).
Some more classic Dutch movies:
-De lift (old, but very scary horror movie)
-De zaak Alzheimer (cop movie of an assassin who's losing his memory)
-Loft (thriller...I think the Dutch variant of the Flemish movie is also available)
-Zwartboek (WW2 movie)
-Koko flanel (humor)
-Rundskop (drama)
-Turks fruit (drama)
-Karakter (historical drama)
-the broken circle breakdown