Alki beach is great. I love it here. There are some other great places to visit, experience and explore close to Alki Beach as well. For instance, drive around Alki Beach, head to Fauntleroy and hop on a boat to explore Vashon Island.
Also, you can head to downtown seattle and find some great places there as well.
Head North a bit and experience Queen Anne and Fremont. Lots to do here in Seattle.