I have a several year old TYAN LGA 775 server board with a Xeon E3120 running as a home file server. What's a popular, quiet cooler for this socket that is moderately priced (< $35)? I think one with a 92mm fan should be sufficient.

Is it better to use a horizontal cooler for LGA 775, instead of a tower? When I do a google image search, the majority of photos are of horizontal heat sinks.

The Scythe Katana 3 runs very quietly with good PWM controlling. It has a 92 mm fan, is reasonably priced, and is 775-compatible.

The Cooler Master Hyper 212 EVO is a bit more expensive, has a 120 mm fan, has better thermal performance, but the fan has bad acoustics. So for this option you'd need to swap out the fan unless you can live with the acoustics.

Here's one for $20. Cooler Master Hyper 212+

Depending on the environment, you might want to replace the included fan with a quieter one. Test drive it first and then decide.

tower or horizontal: both can be great or sucky.

Noctua has a small tower that uses a 92mm fan. It should work just fine. When you eventually move to a newer chip, save your receipts and they will give you a new mounting system for it.... for free.

I think horizontal coolers are always a good idea. The stock Intel coolers are horizontal and it wouldn't hurt to assume that all boards are designed expecting some down draft cooling.

Here is a small downdraft that isn't so bad if you turn down the speed with the included fan controller:
http://www.frostytech.com/articleview.c ... 657&page=5

Looks like it doesn't meet your price though
http://www.newegg.com/Product/Product.a ... 6835118127
Nor does the Noctua
http://www.newegg.com/Product/Product.a ... 6835608016

But here is the XIGMATEK version of the 92mm Noctua heat sink
http://www.newegg.com/Product/Product.a ... 6835233081
It is $24.99 plus you will want to get a Nexus or Noctua 92mm fan for it. But you can try out the stock fan first to see if you can live with it.