After getting into cycling and finding my first purchase, for commuting, wasn't my smartest move, I spend a lot of time researching, and annoying folks on here, before choosing a Surly CrossCheck frame to build up. This wasn't the most cost effective method, a complete bike is more economic, but I wanted to run hub gears, and other different aspects, that didn't come on a complete bike.
I recently sold the frame and forks, with no trouble at all, after a couple of years and about 4k miles. In that time I didn't have any cause to complain about, or regret, the frame purchase. My LBS built up the bike for me and commented that it was easy to do as things fitted as they were meant to. The frame that I replaced it with was a Salsa Vaya, both Salsa and Surly are owned by the same company. My reason for changing was that I wanted disc brakes and vertical dropouts, I was prepared to use an alternative method for chain tension(hub gear) rather than the horizontal dropouts of the XCheck. Apart from that the only difference with the Vaya is it has compact geometry(sloping top tube) and mounts for a front rack if needed. But it shares all the other properties that attracted me to the XCheck, steel frame, clearance for bigger tyres, mudguard mounts, rear rack mounts and ability to take hub or derailler gears.
I agree with Greg, for the sort of mileage you're looking at then spending a bit more on a Vaya/XCheck is worth it and just keep the old MTB for locking up at shops etc. Things to be decided that narrow the search:-
1. self build or complete bike - I could do the former far cheaper now, still not as cheap as a complete bike but a lot closer
2. frame material and forks material - for an allrounder I wanted steel in both areas, unless spending big bucks this would be no more than a 2lbs weight penalty
3. tyre clearances - this can really narrow down your choices, choosing a min and max tyre size also selects the wheels as well
4. brake system - disc brakes, v/canti brakes or caliper brakes - if you want bigger tyres then the caliper brakes aren't a good choice
5. frame fittings - if you want to maximise potential utility then the frame needs to accomodate rack and guards
Once you've narrowed it down then you can think about costs, personally I'd go self build and be looking at:-
steel frame and forks - £400
headset, seatpost, seatpost clamp, stem and spacers - £100
wheelset inc rim tape, tyres and tubes - decent handbuilts from Spa or Wheelcraft for about £350
handlebars, grips/tape and saddle - personal preference here and choice of bars will influence other bits obviously - say £80
groupset inc brake/gear controls, cables, front and rear deraillers, chainset, cassette, chain, bottom bracket - the sky's the limit but £400 would get something decent with STIs if going road bars
pedals, bottle cages, mudguards, rack - I'd allow £100
That gives a pricetag in the region of £1500 but could be down to £1k depending on component choices. You may also have some parts or be able to source some secondhand or in sales, depending on how quickly you want to complete the bike. The other option is to go with a complete bike, at a pricepoint and then change/upgrade as and when bits wear out. Unless you're really sure of what you want then this may be the better option.
) paths and I reckon, if it can carry my weight on those crappy surfaces, then it should be good for most people.
. Running is still my primary sport, but I like the odd 'bimble' out on a bike.