I agree with Dan in general, though per my post in another thread (quoted verbatim from Kelleher Auction's magazine), certain previously popular areas are flat to down. For example France, Germany, Switzerland, Austria, Liechtenstein, Benelux, etc. I find in particular that lots of "rare" German material is widely available on eBay
with no buyers. Sellers are stuck to the notion that Scott's values are a reasonable guidepost for market pricing and won't budge despite a glut of material and poor sales. Scott's is probably ok for these areas as long as sellers (and buyers) realize that the discount from Scott's suggested value is much greater than for more popular areas.
I find the most competition on eBay
for Commonwealth definitives (KGVI - QE2 in particular the recess printed material), China, Korea, French, Belgian, Italian, and Dutch Colonies (though not so much for Spanish Colonies), Indian States, Malaya, Hong Kong, and certain Middle East eg 1920s-50s Syria & Lebanon, Oman, Iran, and Qatar.