How to split a list based on a condition?

What’s the best way, both aesthetically and from a performance perspective, to split a list of items into multiple lists based on a conditional? The equivalent of:

good = [x for x in mylist if x in goodvals]
bad  = [x for x in mylist if x not in goodvals]

Is there a more elegant way to do this?

Here’s the actual use case, to better explain what I’m trying to do:

# files looks like: [ ('file1.jpg', 33L, '.jpg'), ('file2.avi', 999L, '.avi'), ... ]
IMAGE_TYPES = ('.jpg','.jpeg','.gif','.bmp','.png')
images = [f for f in files if f[2].lower() in IMAGE_TYPES]
anims  = [f for f in files if f[2].lower() not in IMAGE_TYPES]

good, bad = [], []
for x in mylist:
    (bad, good)[x in goodvals].append(x)