Having built both an electric and an acoustic guitar, I can quite categorically say that a router is very useful for both, be it routing cavities, body template, trussrod channel (elec and acoustic), binding channels, braces, head thicknessing, form-following routing for an archtop. Etc.
I would also say that bottom-bearing template following isnt too bad, but a further option would be to use a straight bit with a bearing at the top of the cutting part, and a top-template.
DS tape to hold template (body/cavity etc) to wood, and any means of holding wood to bench that you are comfortable with. Ive not used a table router, though can quite see that advantage having one would bring.
I have an older BnQ router, which has a sloooooow start up and sticky plunge, but seems to do the job, and recently bought a Makita doobree which is quite the whippets wedding tackle. It's like the difference between a Ford and an Audi. Both get you from A to B, both are probably reliable, but it just feels so much nicer and easier with the Audi. (btw, I have a Ford
)
I have also used a DeWalt model (cant remember which one) and it was rather nice to, but havent used a Trend.
As far as cutters go, as said above, speak to Wealden Tools. I did for the first time last week, and they could not have been more helpful (actually the same goes for Axminster in the helpful stakes) and a rapid delivery too.
Which cutters? Well, apart from bearing guided straight cutters, you may need a variety of roundover cutters depending on what you want to do with the edges of the body, and a small rebate bit with a mixture of bearings (Stewmac in the states, or Touchstone Tonewoods or David **** in the uK would be best here), a 1/4" cutter for the trussrod channel.
That should do, I think. But there are others on here with considerably more experience than I in luthiery.
Adam