As far as cycling computers go, I use a Garmin as my computer and everything gets downloaded to Strava and Garmin Connect. On the mtb everything is tracked off the GPS on the garmin, on the roadie I have speed and cadence sensors thrown in. I don't use the heart rate monitor, I can feel when I am about to explode.
In terms of clothes, it really depends what you want to spend and what quality you want. On the mtb I wear mtb shorts with knicks or bibs under them. A lot of my stuff is handmade in sydney by these guys
http://www.eleven.cc Its not cheap shit you get off a dodgy website, but you really do get what you pay for. I have a few pairs of knicks that have been going for ever, still look and feel new.
My tip though, don't skimp on the bibs/knicks. You will pay....if you don't pay.