X - Originally the only 1080p panels - used to be the best. Now discontinued. W - Originally came in as the cheaper 1080p panel below the X, is now the top panel on the KDL range. V - Originally 720p panel for KLV range, now 1080p on the KDL range with a few less features than the W (eg no 10bit colour) D - 720p panel, a step up from the original V with 100hz 'motionflow'. Pretty much an updated V. Now discontinued. S - 720p panel, originally cheapest Sony panel available, entry level. Now discontinued.
Sony's current offerings are the KDL V and the KDL W, both 1080p with integrated Freeview HD tuner. I don't know if the older panels are still manufactured, but the KDL ones are your best bet since its more future proof with a 1080p panel and a freeview hD tuner.
Viewed some new X series LCDs in Melbourne last week. Different coloured bezel, they have 100Hz motion flow and an inbuilt (aussie) digital tuner. Noticably less shudder during panning shots. It was called the XMB because it also incorporated the Cross Media Bar menu system a la PS3 and PSP. (Edit: It's actually called the XBR, I was getting confused with something else the salesman was talking to me about). I assume once Sony fit NZ digital tuners they will be here too.
Areas of Geek interest: Home Theatre, HTPC, Android Tablets & Phones, iProducts.