First episode - I heart Steven Moffat
Second episode - I heart Amy Pond (Karen Gillan's quite good too)
Third episode - The pacing is a bit off here, but I heart Bill Paterson, and now I want to watch Truly, Madly, Deeply
Fourth episode - I notice what the fangirls mean, and slightly heart Matt Smith
Fifth episode - I heart Toby Whithouse. Maybe I should watch the rest of Being Human.
If you would like to read more in-depth articles about both new series and old, I would urge you to look at this blog by a lifelong fanboy. Some of the references go over my head but it's very entertaining, so I imagine for readers who've seen all the old episodes it must be ace.