Im not sure where everyone purchases their timers at but walmart has brinks timers for $10 and $15. The cheaper one is a single event timer i think and the other is a really nice 7 event timer. They timers have internal batteries that automatically charge when plugged in.
As far as timers go I have had the best luck with the cheapest ones working without a hitch. At first I spent money on the 7 day digital indoor/outdoor timers but they fail within one year. (intermatic) Some even failed in 1 month. I have had the best luck with the $5 special with removable pins. Cheap but it works well.
I guess i just like the convience of the digital timers. I think intermatic is the brand i use. Thats the brand timer in the lighting section at home depot and lowes right? i think it comes in a red package?
Anyways, the digital timers ive gotten from lowes have worked flawless for years. Ive never had so much as a glitch. I really like being able to set the timers by solar events(sunup, sunset, etc), you cant do that with your analog timer 
X10 works for me, just need to set it up again.
X10 is VERY convienent but its just not reliable enough for me. Ive head way too many disastor stories to tempt fate. I know jim tried X10 years ago and didnt think to highly of it.
Eh, works for lights for me. I suppose if you want to use some sort of timer to do water changes then get something you can trust.(I think you’re crazy if you trust any machine to do such a task though.) If my lights don’t come on or go off I notice and can fix it. I keep a tang that’s supposed to be fed at least three times a day so I check on my tanks at least daily anyways. Not sure what sort of disaster can come up from a couple hours more or less then normal would cause.