Free form? The watch The Good Wife.

Mad Men! Five season down, at least two to go!

Go retro: SOAP. Although it does cut off at a climactic moment, that was how the series was always destined to end, given the subject matter.

Oh! I forgot to mention that I've watched Mad Men through season four.

Of those, I've only seen Buffy, but it's my favorite series ever (even though it went downhill, in my opinion, the last couple seasons), and it has a definite planned-out ending.

I can't remember how Star Trek: The Next Generation ends -- I think with movies? -- but because it's mission-based it feels less cut-off. I liked that a lot.

Breaking. Bad.

I'm currently working through DS9. I left for college in the middle of the series and never got to the end. Watched the first Mirror Universe episode tonight!

Futurama.

Mr. Show.

Someone gave me a Freaks & Geeks boxed set, but I haven't cracked it yet. Everyone says it's good (if you can get past James Franco as an unpopular kid).

FRIDAY NIGHT LIGHTS!

From your list, I watch Dexter, Boardwalk Empire & The Wire. All are really really good and are a not to be missed

Oh, yes, Freaks & Geeks! Only one season, but a good ending.

Oh, what a good show. Oh.

The Wire is a must-see. Dexter is good for the first couple seasons, but gets very bad very quickly.

Not on your list, but also highly recommended:
Damages
Homeland
The West Wing

In the vein of "Go Nuts": The Increasingly Poor Decisions of Todd Margaret. Netflix only has season one, and it's total David Cross-y cringe humor, but I loved it. I can't wait to watch the second (and last) season.

I'd put The Wire and Buffy into a Seinfeld/Simpsons category, where it's like they are part of some minimum pop culture requirement. So watch The Wire. Buffy's first couple seasons are pretty low production values though, which might bother you given all the other things you are listing.

I'm surprised no one has recommended Doctor Who. I gave up on it awhile ago, but "Blink" was an amazing episode.

If you saw BSG and you're okay with how that ended, go ahead and give LOST a shot.

Why don't comedies work for you guys? I never get tired of recommending Peep Show. Similarly: Arrested Development, the Venture Brothers, Community, The Office (UK)... Those can all be intense and dark and require a mood. For more watchable stuff where you see one and then you are smiling and happy and want to see more more more, I'd say: The Office (US), Modern Family, and 30 Rock in its prime.

Modern Family kind of fascinates me because in so many ways it's just HERE'S YOUR FAMILY SITCOM show. It's played utterly straight, but it's funny as hell anyway.

Big Love started off awesome, and the first and second seasons were really interesting. Then it got stupid. Same with Weeds.

If you want comedies, I also like Modern Family and How I met your mother.

The Wire is the best of the best.

OMG! I forgot Homeland.
I am working my way through the first season now (2nd season just started but I dont have fancy cable anymore) and I love it.

I'm going to have to go back and try The Wire again. I watched the first season but couldn't never really warm up to it.

The Wire is incredible. Give it a few episodes (at least) to warm up: it's got a large and complex cast and it doesn't do the spoon-feeding (repeating character names Dale-Carnegie style, for example) that lots of shows do in the pilot.

I second Eideteker's rec of Breaking Bad, but with reservations. I felt like the first three seasons were compelling but flawed, with the characters operating more like bad-decision machines wound up by the writers: totally worth watching but not Great TV. We just blasted through the 4th season and I cannot believe how much better it is: more internally consistent, better motivated, and with the women fleshed out substantially. (In the first season or two, the women exist basically to frown, scold, and shop.)

Dexter is a classic hate-watch chez nous. I love Michael C. Hall, hate the secondary and lesser characters, and love/hate the show.

I cannot be objective about Buffy. I love Buffy. I love Buffy late in the run, when other people think it starts to fall apart. The first season is pretty goofy, so hang in there.

nthing The Wire, too. Absolute must see. (And I'm very, very jealous you have it to look forward to).

You've probably seen Homicide already, since it's older, but I thought I'd mention it, just in case. Utterly awesome, on par with The Wire and Deadwood (last season's weaker, but there's plenty to see before then).

Grey's Anatomy and House are good, if you like medical, and quite addictive (I found myself staying up till two in the morning to catch reruns of Grey's over the summer).

Of course I love anything Star Trek. Next Gen's my favorite, then Voyager, which is also excellent. Deep Space Nine gets a little "spiritual" for me at times (and you will HATE the series ending--I know I did), but it has its moments. And, of course, if you haven't seen the original series, you must, must I say! (Corny as the old special effects are.)

I also loved Charmed. It's arguably more a "chick" show, but a lot of fun, if you like supernatural/witchy stuff, which I do (you've probably seen it).

Days and Nights of Molly Dodd was also great for a couple seasons, then kind of fizzled, but still worth seeing, and for the down-but-not-out amongst us, The John Laroquette Show, where he manages a bus depot, is terrific.

Hmmm, I guess that's it for now. I'm sure there's more... (I watch entirely too much TV.)

Thanks for all the input, bunnies! Y'all have mentioned some series that never crossed my mind and I'm definitely interested in.

I did forget to mention a few that I/we've seen, mostly older series (Star Trek, House).

Also, the series must be on DVD. Canada gets Netflix only by streaming and we don't want to watch stuff on our computers. Hulu is unavailable in Canada.

Thanks again!