The Egyptian Cotton sheets I bought at Costco are great. They weren't too expensive either. Also, the best way I've found to ensure your bed is super-comfortable is between the sheet and the mattress, you put a duvet (comforter). This makes a huge difference to bed comfort (and also helps preserve the mattress, being an extra washable layer to absorb perspiration).

Of course, you have to use fitted sheets for this, to hold the duvet in place.

I think we discussed once that "duvet" is used a lot of different ways in bedding. Here in the US, a "duvet" is generally a cover you put OVER a comforter (like, a down comforter), which then goes on top of your flat sheet. Between your fitted sheet and your mattress, we use a "mattress pad". It's all very confusing.

300 minimum thread count in your sheets. Also, stick to 100% cotton, no polyester.

I really like those sheets that are made from beech trees. Yes, that sounds insane. But they're real! You can check 'em out at BB&Beyond. They have regular beech sheets that feel like flannel, and then satin-like ones, which feel like heaven.

OK, what I mean is the microfibre eiderdown-type things that you put inside a cotton cover. Usually they go on top of the bed to sleep under (in the UK anyway) but if you put one on top of the mattress, it makes the bed seem very luxurious and extra-comfy. In the UK you can pick up a duvet in the supermarket for under £10.

Yeah, Senyar, that's called a duvet here in the US too. A duvet cover is normally what is used to - well, cover a duvet. It's like a big bag for your duvet.

Ha, unsurprising and TPS just totally contradicted each other's meanings of "duvet".

mr. gaspode is like TPS in that a "duvet cover" goes on the "comforter". I'm always like "why the hell don't you call it a "comforter cover"?

Anyway, everyone knows it's 'doona' and 'doona cover'.

I don't think that I ever heard the term duvet before seeing in a Metafilter thread.

I think of a "duvet" (or "comforter") as a feather or fiber-filled lightly quilted blanket that goes inside a duvet cover, which is made of sheeting fabric. The difference in my mind is that a "comforter" generally has its own patterned fabric and isn't meant to go inside a duvet cover, while a duvet is. However, white down "comforters" often go into a duvet cover, too.

It looks like there isn't complete consensus on the terms even in the US.

Miko is completely correct on the duvet/comforter issue.

Anyway, with regard to sheets, I love, love, love flannel sheets in the winter. Just buy the best sheets you can afford; you get what you pay for (unless you're paying for a big-name logo).

I'm in the market for new sheets too so I've been shopping around. Overstock has very good deals. Look for 100% cotton. Egyptian cotton is best. I like 400 TC ish. The higher the thread count the the better, usually, but if you get really high (1000) they start off feeling stiff and you have to wash them many times to get them to feel soft. They will last forever, though, assuming your dog doesn't bite them playing with a tennis ball (ahem).

My favorite sheets are also Egyptian cotton, somewhere around 250 or 300 thread count. I bought mine at Bed Bath and Beyond - their clearance section is usually pretty awesome, and they're always sending us the 10% coupons in the mail.

I've had flannel sheets too, and they are nice in the winter, but I find that they get pilly after a while. But maybe I just had cheap sheets.

If you have a TJ Maxx or Ross Dress for Less near you, check them out. I buy my sheets there and they're usually around half the price they are at Bed Bath & Beyond. Granted, you kind of have to dig and the colors are somewhat funky, but I got 400 thread count Egyptian cotton queen size sheets (burnt orange) there last spring for $28.

Totally love these sheets. (And love their towels even more.) Also these sheets.

My understanding of the duvet/duvet cover/comforter dynamic agrees with Miko's.

My "aunt" Dagmar's wedding sheets. She isn't my aunt, but my gran and my mom and myself called her aunt Dagmar, I forget whos aunt she actually is, she's related to gran. Anyway, sad story, she was stunningly beautiful as a young girl, tall, slender, blond wavy hair, huge eyes, all that. She was engaged to a very handsome young man who was serving in the army. So, she bided her time making her wedding stuff for her bridal-chest, the bedsheets, the pillowcases, the nightgown - all the things a young woman needs in her first own home. Then disaster strikes, she finds out that she has an illness that will deform her. She does the "honorable thing" (in her mind) and mails her fiancé the ring, refusing to let him see her again.

Anyway, long story short, she lived a long and happy life, albeit alone (and for 60 years with her best friend that she met in the hospital who had the same illness as her). The illness only took her nose, we still thought she was pretty, but of course going from the towns prettiest face to noseless was a bit of a jump for her.

Anyway, I ended up with most of her wedding items (I have yet to use the gown, hand sown lace all around, all done by her! It's amazing!). And whatever cotton she used, it's fantastic. I shouldn't have, but I opened my bridal chest early and have slept on her pillowcasing for 15 years. It's amazingly cool soft cotton. Nobody else gets to sleep on it (I throw big drama queen fits over this pillow case) I haven't used the duvet-casing or sheets yet, but they are all the same quality. 15 years of washing and that pillowcase still holds up too. It's much thicker than anything I have seen in stores, I think it's like a million thread count 'egyptian' cotton. When washed I have to run it through one of these to get it wrinkle-free. It's got beautiful handmade lace running across the side.

Miklas now teases me that he knows I have a bridal chest and asks why he never gets to see me in my nightgown. And I scoff you have to MARRY me for that!

oh sorry, did I just ramble? TMI & tl;dr -It's gotta be thick egyptian cotton, the kind that feels cool to your touch in the stores. It'll last forever when treated right.

I'm not really versed in the technical details of "thread count", but from what I gather, the discount retailers play fast & loose with the term, and inflate the truth... which is all just flimsy justification for this observation:

We have "600-count" sheets from BBB that cost $30 and feel like cardboard, and a 464-count set from Restoration Hardware that cost 10X that (sshhhh don't tell Mrs. Triode!) which feel like the taste of a perfect July peach or a warm hug from Mom. They've lasted 5 years, an only recently sprung a small tear, which prolly has more to do with the dog sneaking on the bed.

To quote Mr. Bueller, "It is so choice. If you have the means, I highly recommend picking one up."