A standard room is just that--a room. Youmight possibly get an upgrade to a deluxe room, which would be a room with a view or a balcony or both, by showing your Starwoods card at check-in.
Club and concierge are the same thing at the SD; Club level gives you access to a lounge where there are breakfast items in the a.m., and lighter fare in the evening. You can see a sample menu on Glos FAQ. There are also drinks available, including bottled water, which you can take with you to the parks.
Club is especially nice if you have a large group, because it can save you a bit of money if you take advantage of it.
I decided to go with Club level for the first time this month. I will let you know in three weeks how it went!