This place has recently moved making pretty much everything I wrote kind of useless. I'll strike it through but leave it here as I guess it could help you get a feel for what kind of place the new bar might be. Seems that it's not so central anymore, but I'm sure it's still worth a trip. Map and address are updated to the new location, but the picture is of the old place. Sorry.
Monday-Saturday, 17:00-01:00 (maybe from 15:00 on Saturday, but their facebook doesn't match their website, so who knows?)
内山 3-22-11, Chikusa-ku, Nagoya
So, three good places, two particularly good ones. It was nice that we didn't encounter a cover charge anywhere in Nagoya. People say that the prices are a little high, but coming from Tokyo the difference wasn't so apparent. I think Kyoto and Osaka people might notice the difference a little more. Also, all three places were non-smoking which is nice too. There seems to be a trend towards to non-smoking recently which for me is very welcome indeed. Like I said, Nagoya is not so difficult to get to from Tokyo if you take the Shinkansen, but it guess it's not something you could really do every week (unless you are very rich indeed), but it was definitely worth the visit. Y Market is close enough to the main station (10 minutes walk) for you to stop off there for a couple of beers if you are passing through and have a JR rail pass. Perhaps the next time I make it down to Aichi there will be more places open, but with these three, they already have enough to entertain you for a weekend of boozing.