Sorry to disappoint anyone who thought I was chatting about sexual positions.

Actually, I want to pick the collective brain of org goodness about dogs ...
Me and the Mrs want to get one. She is the impulsive one in our relationship saying yes, and I am the boring logical thinker dithering about whether we should or not.
Basically the thinking is, we both grew up with dogs in our families, so we both know what they entail. i.e. Food costs, walks every day for the rest of their lives, potentially expensive vets bills, having to organise someone to look after them when you want to go on holiday, picking up crap from your back garden, chasing after them as they run after a rabbit onto a main road, farts that make your lungs bleed and your eyes water, and of course unconditional love, company and endless entertainment.
The benefits are especially good for me, cos as someone who works from home, the only company I have is the odd phone call, Judge Judy at midday and a stuffed penguin called Goo Goo. There is also a little one called Nano, but we rarely talk. A dog would be here with me all day, so he'd have company, I'd have company, and I'm perfectly placed to feed him and take him out for his strolls.
We've done all the research into breeds. Carley had some mungrel when she was a kid, and my family has always had dalmatians. We're after a lab, because they seem to be the most placid, while also being intelligent (so I can train him to juggle and stuff). But being my usual self I'm thinking, what if I have to start working away from home, or what if me and the mrs split up (god forbid), or what if we want to move abroad (which we possibly will in the future), and do I really want to commit to driving to a forest and walking, rain or shine, for the next 14 years of my life?! (We only have a passat saloon too)
The other problem I have, is when I was about 14 I have a strong memory of the dog I grew up with slowly dying. I remember hold his head and stroking it as the vet injected him in our home, killing him, and then he shat his load all over some newspaper we'd got him to lie down on as he died. So dignified! Being the thinker I am, I have always thought: do we put animals down for their benefit, or ours? If you were struggling to walk and life was a bit miserable, would you want someone else to make the decision to kill you? That experience was so traumatic as a kid that, when my parents second dog was getting close to being put down, I stayed away from home for 2 months (I was at uni at the time). I distanced myself from her, and severed the attachment so that I didn't have to deal with her being put down. Pretty sad really, since I was her favourite in the family.
So you see my dilemma. I love dogs. It would be awesome to have some company at home during the working day. I'd give the dog a great life. But I can't decide if that benefit is worth all the inconvenience with walks/holidays/where you can live etc. and watching them slowly die in the last year of their lives, before making that decision to have them put down. With this dog being mine this time, and spending it's whole life by my side, I'd imagine it'd be a really heavy blow.
So there ya go. Another example of my over thinking. What do you guys reckon? Should I do it doggy style?