The problem in recommending a "good" revolver is your price or budget. If your Dad has been happy with your Colts, the first one I'd look for is a Trooper Mark III in 22LR (probably a 6"). It will be a nice mate to yours. I shoot my Trooper Mark III in 357 more than any other 357. Used to own a Python or two, but sold them off. I won't even mention the great Colt Diamondback due to prices these days, but it is out there. It's my favorite modern 22 revolver and has been for a long time. Other excellent Colts are the Officers Model Match (6"), Trooper (4"), and Official Police (4" and 6").
The Trooper Mark III 22's didn't sell well for Colt back in the day. But I think it was because they were heavy compared to the Diamondback and not that much of a savings then over the cost of a new Diamondback. The Trooper Mark III is an excellent 22 revolver and the equal of a Smith of that time period. Don't dry fire them however.
Now.... in the Smith & Wesson line, the current Model 617 is excellent. I honestly prefer the 4" in that one due to the full barrel lug. Older but great ones have already been mentioned, the Model 17 (6") or Model 18 (4"). Both are great and I own one of each now. I picked those up last year. Figure $450-$600 for a pretty nice one of either. Smith is going to be selling a Model 63 (J-frame) with a 5" barrel this year. That might be a reasonable choice, but I prefer the larger K-frames (17 & 18) for general shooting. I'm going to buy one of the Model 63's, but I have lots of 22 revolvers.
In the lesser priced 22 revolvers, you are going to have to "know" your father as to what he might like or prefer. Of the ones that have been available, I lean toward the H&R 999 Sportsman but it will never be a Colt or Smith in quality. Heavy double action, but it is a dream to load and unload with the open top design.
The Charter Arms Pathfinder is another one that is out there now. I have not shot one but GunBlast did a review on one a while back. The review is on their website.
Of the single actions, the Ruger Single Six is the best of the current manufactured ones in 22. I prefer the Colt New Frontier as it is generally more accurate and the fit and finish is quite nice. They will cost you in the neighborhood of $500-$600 for a nice one though these days.
I would stay away from small framed revolvers in general for general shooting, but the Model 34 was nice as I hope the Model 63 is when available later this year.
Can't really comment on the Taurus lineup as I have not owned one.
Raise your budget number and choose a great 22 revolver rather than an average one.