My family (me, husband, 2 golden retrievers) loves OB and has visited every summer since we discovered it in 2010. Each of the last four years we have stayed at a different large-dog-friendly vacation rental. So far, our 2013 stay at Blue Heron a Cottages has been the best overall experience, taking everything into consideration: Rates, fees & deposits, location, and amenities. Your dogs get a super nice large yard(shared with 6 other cottages so it helps if they're good with other dogs and people), which is very rare in beach towns as it's prime real estate and properties are built out to the max. The cottages themselves are nicely appointed with new Ikea furnishings and nice hotel quality bedding and linens. You get use of the beach cruisers which is great because it's sort of a long walk to the beach but if your dogs are good at running alongside as you bike like ours are, it's a quick and fun ride to Dog Beach. Sure parking is tough, that's just the way it is near the beach in summer. It really wasn't much of a problem for us, you park, you unpack, maybe go out for groceries, then you don't really need to drive much after that, OB is a great town for walking (or bicycling!) around. If you've been to OB then I probably don't need to sell you on it, there are so many great restaurants (all large dog friendly!) we have a hard time making sure we hit all of our faves during the week we're out there.
Try the cottages, they're worth it!