Two sets of cycling clothes, wear a set on one day. Shower and wash that days clothes when you get to the B&B in evening. Leave to dry whilst you grab a pint and some food. Use the spare dry set the following day. This means that if your first set do not quite dry in time then you can finish drying them on the second evening and still have dry clothes for the 2nd days ride. Nothing fancy, bar of soap and shower - stay low tech. The soap gets used for body, hair and clothes - just like it was in the 50s and 60s, though I do treat myself to Dove moisturising soap
Waterproofs and warmers - yup even in summer. It depends on where your touring but a little bit of rain and some height, such as on the moors, and cycling can be very unpleasant. The only time I havent taken leg warmers was touring the Scottish borders in late September/October. It was cold enough to take a microfleece hiking jumper and long leggings and wear them every day.
Electricians tape - not quite duct tape, just electrically insulating black tape. Some folks take a bit of duct tape, tear lengths off and stick them on the inside of your panniers for when you need to make running repairs (re: bodge).
Sustrans maps - only used if were using a Sustrans route. Never used during the day, just used in the evening to read up on the next days exploits. When we haven't been following Sustrans routes we just print the appriopriate OS maps out on a works laser printer then laminate them (along with instructions on where we stay in the evening). I'll upload this years route document out so you can see what I mean.
I've never really got on with the Garmin 705 mapping. I've been privileged enough to own a SatMap device and the complete UK 1:50k OS maps which is a remarkably effective combination for both distance cycling and hiking.
Here is the route card that we print and laminate:
http://www.malia.info/stuff/misc/cycle.tour.2011-01.pdf
You can usually add between 5 and 15% to the expected daily distance and the estimated ascent is normally miles off. Mapping on a software package always seems to significantly underestimate the totals. For instance, this years day 1, we plan to do 81 miles, but I wouldn't be surprised if it's closer to 90.