With the Harry Potter movies, I got the first 5 on dvd. But then blu-ray came out and I've started getting them in that. I'm also going to go back and get the first four movies on the Ultimate Editions that just came out.

Nope

I did re-buy/upgrade Dexter S1 + S2 in BD after already owning them on DVD though.

Smallville 1-4 DVD

Smallville 5 - HD-DVd

Smallville 6-7 Blu-ray

Smallville 8-9 DVD

I do not the blu-rays of season eight and nine, most likely will just give the DVDs to a family member that likes the show and buy the blu's in the future.

I switched to Blu-Ray with Doctor Who after Season 4.

This.

I haven't purchased a single thing on DVD since I got my launch PS3. Nothing but Blu-ray ever since.

So far I can only think of a few TV shows in our library that have even had a Blu release, and we've passed on all of them to date.

Burn Notice Season Two - Given how horribly reviewed and rated this release was, it's pretty easy to pass on this in favor of the DVD release (when we eventually get around to it).

The Sopranos - To date, only the first and last seasons have had a Blu release, and I'm just not going to re-buy the show a season at a time. If HBO releases a complete series box in Blu, I'll be happy to find a buyer for one of my kidneys but in the meantime, I'm content with the DVD seasons we already own.

House, M.D. - We thought about getting Season Six on Blu, but the right after Christmas, Amazon had the DVD on sale for $14.99. We may re-watch movies often, but rarely a season of a TV show so for that kind of savings, it was easy to forgo the superior A/V quality of Blu-ray in favor of the considerably more attractive price.

I am interested in eventually getting around to Star Trek and Star Wars: The Clone Wars on Blu-ray, but so far neither has been a priority. And, to be honest, I'm perfectly content with the three DVD box sets I have of the original versions of Star Trek. I still haven't completed The Next Generation or even begun Deep Space Nine, so re-buying the original series on Blu just isn't important to me. (That said, if Paramount were to pull out a Blu release of DS9, that would go directly to the top of my Wish List.)

seems...dumb? How about less expensive

Well I can understand some people don't want to upgrade over price but I know a lot of people are just the types who need to have their cases match up and go crazy if they have different types.

Price argument aside, this is the only correct answer.

Harry Potter and the Philosopher's Stone - (Original DVD died, so I just bought the BR) BR
Harry Potter and the Chamber of Secrets - DVD
Harry Potter and the Prisoner of Azkaban - DVD
Harry Potter and the Goblet of Fire - DVD
Harry Potter and the Order of the Phoenix - BR
Harry Potter and the Half-Blood Prince - BR
Harry Potter and the Deathly Hallows Part 1 - BR

Score will be BR 5 and DVD 3 by this Nov/Dec.

Will not be replacing the older DVDs for BR, well maybe if I have the money and they are $7.50 each.

If Blu is available it's my only option. Now if I have to go back and upgrade ala Lost that's when price becomes a factor for me. (still don't have season 2 and 3 on Blu)

Just realized I've bought the two most recent Harry Potter movies on Blu, though I made sure to get the combo packs so I still have DVDs of them also.

I dont mind switching. Moving forward, I'm gonna try to get the majority of titles I buy on blue ray. I am not planning on rebuying previous seasons that I already own on dvd. So shows like smallville, Supernatural, and Fringe will have dvd releases, and later seasons will be blue ray.