I have always loved Gymboree clothing. It is well known for being adorable, well-made and durable. Their socks are no different. With any clothing line Gymboree produces, they always have matching socks. They also make socks that are standard colors that can be worn with any outfit.
Gymboree socks, similar to most things from this designer, tend to be expensive. When purchased on sale, with a coupon or in conjunction with their Gymbucks program they can be less costly though so make sure to look for these things.
I like these socks because they wear well. The colors or designs do not fade after repeated washing and the elastic does not wear out. Also, they run true to size (in fact, my three year old with a big foot can still wear his 2T socks from last winter). If you happen to purchase a Gymboree outfit, chances are they will have the perfect socks to match which makes dressing for picture taking and special events easier. Smaller sizes have small rubber dots on them to make little feet more steady on slippery surfaces. These socks also have the size printed on the sole which helps you match socks and keep them separate from a child with a size that is slightly different.
Overall, I highly recommend Gymboree socks! I find that they're definitely worth the small splurge.