Is there a specific brand anyone uses?
I just use whatever the local PC "Chop Shop" has for sale. Luckily I was
able to get a nice supply of 50-pin SCSI ones when they were still somewhat
common. They're the main thing I use, as I use them on my PDP-11's.
These days something to consider is how well they'll allow cooling of the
drives, this tends to mean going with a more expensive model. Plus as has
been pointed out, if you're using newer EIDE drives (ATA/66 or better) you
need the newer trays that support them.
I do have a couple PC's that use the EIDE trays, one of which is in storage,
the other doesn't really need them as all I've done with it for the past
year or so is run Debian a couple times.
Zane