Caching User Data In Application?

What's the best way to cache web site user data in asp.net 4.0? I have a table of user settings that track all kinds of user or session specific stuff like the state of UI elements (open/closed), preferences, whether some dialog has been dismissed, and so on. Since these don't change very often (for each user, anyway) but are looked up frequently it seems sensible to cache them. What's the best way? These are the options I've identified...

Store them in HttpContext.Current.Session directly (e.g. Session["setting_name"]) Store them in HttpContext.Current.Cache Use a global static dictionary, e.g. static ConcurrentDictionary<string,string> where the key is a unique userID + setting name value Store a dictionary object for each session in Session or Cache What's the most sensible way to do this? How does Session differ from Cache from a practical standpoint? Would it ever make sense to store a dictionary as a single session/cache object versus just adding lots of values directly? I would think lookups might be faster, but updates would be slower since I'd have to re-store the entire dictionary when it changed.

What problems or benefits might there be to using a global static cache? Seems like this would be the fastest, but I'd have to manage the size. I could just flush it periodically if it hits a certain size, or keep a cross reference queue and remove things oldest first when it gets to a certain size. Does this make any sense or is it just trying too hard?