Like Steve Howell, Dr. France Cordova (by the way, she is female if you aren't sure!) has been involved with the AAVSO for some time, and a lot of what she had to say was relevant to the visual observers present. Visual observers have long been in demand for multiwavelength observations (we observe in the visual and then this can be compared with findings made, say, in the ultra-violet band). The advantages of observing a given object in more than one wavelength of the electromagnetic spectrum can be demonstrated by looking at these views of the famous Crab Nebula in Taurus (Messier 1). Note how, for example, the extreme ends of the EM spectrum (raio and X-ray) reveal the different extent of the radiations in their respective sensitivities. The un-labelled view in the bottom left-hand corner is the visual image, taken with the Palomar 200-inch.
Since XMM-Newton is a satellite in high Earth orbit, it can cover several outburst cycles of a Cataclysmic Variable for instance and so simultaneous optical / High-Energy observation is a good bet. In fact there have already been useful results from several CV's including such "old friends" as OY Carinae and VW Hydri.
Other types of stars which have been observed with Newton are the Polars. Here there is no accretion disk; instead the material is drawn off the late-type star and into a small region on the primary. It has been found that this "accretion spot" precesses (that is, gradually moves about on the surface of the star (with reference to the background stars for example) over the course of many orbital cycles, similar to the way the Earth's poles slowly move with reference to the background stars.