I find this a very interesting topic for me, for some reason. I love loading up trance songs from my iTunes into a sequencer and finding out the tempo by matching the beats to the measure bars. Something interesting turned up, which is that many songs have a tempo of 138 BPM (which is one of my favorites when I produce.) I decided to get produce a list counting all the songs within each respective tempo.

I've only looked at a few songs so far, but here is the breakdown of part of my trance music library and the tempos typical for trance. There is a huge drop at 139 and then a spike at 140.

128: 4
129: 1
130: 14
131: 2
132: 4
133: 1
134: 12
135: 12
136: 14
137: 15
138: 51
139: 10
140: 35
141: 5
142: 3

You don't have to post a breakdown like I did, but I'm just curious to know what turns you guys on to, say 138 BPM, but not 137 BPM? Or why is 140 BPM more appealing than another? When I do uplifting trance or tech-trance, I generally keep between 137 and 142. Tech-trance is almost always between 139 and 142 when I work on something, while uplifting ranges between 137 and 140. Lately, my songs have had higher tempos. I upped "Flashpoint" from 138 to 141 and a new song I'm doing is going to be at 139. When I produce house every now and again, I'm always between 122 and 124 BPM. I personally loathe producing anything at 135, because it seems too wishy-washy, like it wants to be both progressive-like (less than 134) and uplifting (136 and up.)

On another point, it seems like you'd want to scootch your tempo down a wee-tad when producing, so that if you ever pitch up when mixing, the melodies become slightly stronger and more inspiring without necessarily changing the musical scale.

I generally go around the 135-140BPM range, and I tend to go for more even numbers because they are the traditional BPM's in Trance I guess. I have experiemented with slower stuff though, such as one of my new productions being at 128BPM.

pys-trance tempos generally are a bit faster than the typical progressive or uplifting trance tempos, maybe around 145 or so.

It really depends on the mood for me. Generally for trance I'll go anywhere from 135-145 BPM. But even songs where I use the same BPM, depending on what kind of drum track I create, it could sound faster or slower than another song with the same tempo but different beat (maybe by using a more busy high hat rhythm or doing anticipated breakbeat-like snare hits.)

My personal favourite is about 136-138 range.  I tend to keep most of my mixes and productions in this area.  I just really love the feel of the tempo and IMHO is right in the sweet spot. 

Most mixes I do are at 140, when I get to do whatever I want. If I have to slow it down a bit, I try for about 132. I hate the area in between because it goes with so many productions these days that try to fit both trance and progressive house categories at around 134 or 135. It feels like kind of a cop-out to me. When I produce, I typically go for 138 to 140. Sometimes I do some slower stuff, but I stay way away from 128 since Deadmau5 is the only reason that friggin' tempo exists! XD

All my mixes really range and so does my music collection but on average I start in the 125s and build up to 140. I think the range of music in those diff BPMs makes for a really interesting listen.