It's an interesting question, and I think it seems that to some extent, the higher you climb with regards to higher education (i.e. bachelor's degree -> master's -> PhD) the less it starts to matter. However, I do think that in the case of the recruitment of young graduates (i.e. very early twenties in particular), the university from which the degree came can indicate several things- particularly aspirations, ability at the time of application (as it is accepted that 'passing' the interview stage at universities such as Oxbridge isn't easy), perceived potential etc. Although people can change rather dramatically in the 3/4 years a typical degree lasts, I guess it's similar in some ways to how universities look at GCSEs as well as A levels when you initially apply. Sometimes past performance can be quite telling too.