Wow this is one of those "can of worms" questions...
Ultimately there are factors that will influence you as an individual so there are concessions that will need to be made. Kids, money, parking at your house... and of course all these change with life changes.
My 87 bronco was my daily driver when it went from stock to a 460 on 1 tons and 37's. I didn't live with my parents but I did the swaps at their house.
I did acquire a daily drive shortly after that and it almost got me kicked out of where I was living because we had too many vehicles.
anyway for current life; we have a 98 civic, an 00 super duty, and a 99 xj. we own all of them outright. Married no plans for kids... early 30's...
most insurance companies will allow you to drop insurance on a vehicle if you are not driving it. Allstate calls it "in storage" I call them up say that I am putting the jeep "in storage" and my insurance bill goes down until I "take it out of storage" they are super cool about, to get coverage back on I just have to leave it on their answering machine and I have insurance at that moment. When it is "in storage" i put a big note on the steering wheel so I don't drive it without insurance.
I really want to keep my wheeling vehicle street legal because it is fun to drive on the road and if one of our other vehicles breaks we still have two vehicles. (of course a few months ago my wife got in a car accident that took our civic off the road for a week and the jeep didn't have axles under it so that didn't work out as planned...) We may get a trailer but a vehicle that has to be trailered everywhere is kind of a pain to use. Also if I only drive my jeep in Moab it will break down in Moab. Unless we have insurance off of it, we will drive it at least once a week, we took it to the Olive Garden the other night.
I have a garage in the back yard of our house, it is great, but if I put a trailer on the rv pad I couldn't get a vehicle in and out of the garage. (I potentially could put a trailer pad on the other side of the house)
Our truck is a 5.4L 2000 superduty it would struggle to pull the jeep on a trailer, but if you search the "tow rig" area there are some pretty good arguments to getting a gas tow rig. (the added expense of a diesel is a lot if the only thing you "need" it for is to haul ass up the hills going to moab, a gas truck looks a lot better when thinking of it like that)
For a daily driver, You can find older imports if you don't care what you are driving for cheap that are pretty cheap to own. I have a co-worker that picked up a hyundai accent 2 years ago for $1000. he has had to put a few hundered dollers here and there into it but he has really gotten his money out of it. But a car like that you probably won't want to jump in and go on a long road trip. Our Civic is a commuter car and a road trip car (40mpg highway) so we wanted something a little more reliable than a $1000 car. Plus you typically want your wife to have a pretty reliable car. We have snow tires for the civic and a set of Michelins and both sets of tires were about $1200.00. (btw if you have never had a set of snow tires, they are 100 times better than you would think...)
Our truck we put less than 5000 miles a year on. it has 214,000 miles, i bought it from my dad he bought it new with 10 miles on it. That truck has been the most reliable vehicle ever built. It had it's first real problem at 208,000 miles, the fuel pump left me standard... in my garage... It has the original motor, tranny, clutch, t-case, alternator... I can count the things that have gone wrong with it on 2 hands and most of those are things like the dome light sticks on because of dust in the door switch or the clutch cruise control switch failed so the cruise control didn't work. But if I start towing the jeep with it it will need a new motor and some kind of power improving device. It is really nice to have a truck. It is easy to make a Home Depot run for whatever, or a junk yard run or go pick up an axle.
uh what was the original question...
"My question is, is it worth it to have a dedicated trail vehicle versus a built daily driver?"
I guess if you buy a crappy car and remove insurance from the wheeling rig when not in use it can be cost effective... It is hard to factor in the "cost" of not having to stress about getting to work on monday. I have driven home from moab in front wheel drive in the bronco... with a lock-rite in the front axle... it was nice that I had my car so I didn't have to deal with the broken rear yoke right away.
I think most guys will say it is "worth it" but probably not really cost effective, but this hobby is not cheap, if you want to play you gotta pay...
I thought I would ramble more...
nathan
99 xj
build thread
http://www.rme4x4.com/showthread.php?t=83436