By Ras's recommendation, I went to IKEA and bought some LED light bulbs.
Let's start with my target: the 90-lumen small bulb that I use in my salt lamps:
you can see, 90 lumens are quite adequate for this purpose - could be the
equivalent of 25W traditional bulbs. BTW I broke off the glass cover and
used it like this:
Well, the 200-lumen IKEA is just not adequate for my purposes: it is around 40W traditional equivalent, while the Philips CFL is ~60W, does not provide enough light to replace. It seems that LEDs consume about 50% the power of CFLs, and still pretty expensive: the only real advantage is that LEDs are much more compact in size.
I'll try buying and stripping the 400-lumen IKEA version as well: too bad it only comes with an E24 lamp base, so I can't use it unless I manage the conversion.
I have several converters like this one, from GU10 to E14:
One more success story, not related to IKEA: