Yes, this question seems to come up at least once a month.
I've been producing for 14 years now and have a fully sound proofed recording studio (which cost me thousands), access virus ti, andromeda, ssl-x desk, cyclone analogic TT-03, mopho, every softsynth in the world, sylenth, synth 1, trillian, fm-8, pro-53, zebra2, genesis, pro-53, albino, v-station, siverbox, massive, z3ta, poizone, discovery pro, hypersonic.... waves diamond bundle for mastering etc etc.
I always rewire Reason 4.0 through FL Studio. That way I get access to subtractor, combinator, maelstrom, redrum, get the low CPU usage from reason, then use that to layer with synths in FL Studio.
For 14 years I've been tweaking knobs and programming synths so I can recreate virtually any sound.
As far as selling samples, I only started doing that 2 years ago.
I sell very unique, hard to find sample packs. 90% of my samples are layered. Reverse claps, reverb claps, snare rolls, multi-layered bass kits (my bass kits are as deep and gritty as they get), multi-layered bass drums, tons of unique noise fxs, multi-layered synths, etc etc.
This is one of my latest WIP's (I do not share my soundcloud on here). Made this bassline with my mopho then layered the virus ti over it, tweaked for a couple hours and it's almost done:
http://www.speedyshare.com/PAPJD/Pitched-Pro-Bass.zip . That's just 1 sound lol. So it generally takes me months just to release a new sample kit. I also sell very unique FLP's for FL Studio. Then another unique thing I do is offer individual samples on my site. You can demo every single sound and if you want to buy a specific sound, rather than the whole pack. I sell them between $2-$5 each. My full sound kits go anywhere between $50-$150 and people buy them cause they KNOW I put a lot of time into them.
The best piece of advice I can give is do NOT release shit into the market place. Do NOT demo 5 of your best sounds, then the other 30-40 sounds in your kit all sound like shit. People will tear your asshole wide open on forums, they will not recommend you, you'll get very few returning customers, etc. Do NOT spam music forums. Do NOT sell sounds if you can not program a synth! Actually interact with people and build up a reputation. I have accounts 8 years old on certain music forums with thousands of posts.
Brand yourself for quality, not quantity. Take your time. Look at Brazzers porn site. They put A LOT of time and effort into their videos, high production quality, they built up their site very slow over the course of 10 years. But now they're one of the most well known porn sites.
Do the same thing for your niche. Give people the highest quality crack you can produce, and they WILL come back for more.
-BB