I have found interesting article in gamasutra which has top 10 sales numbers for steam games:

Estimated Top 10 Titles & Expansionsfor October 2010, by Units Sold:

1. Fallout: New Vegas (Bethesda Softworks) - 308,000 Units ($49.99)
2. Call of Duty: Modern Warfare 2 - Resurgence Pack (Activision) - 228,000 Units ($7.49)
3. Left 4 Dead 2 (Valve) - 178,000 Units ($15.00)
4. Counter-Strike* (Valve) - 114,000 Units ($9.99)
5. Half-Life 2: Deathmatch* (Valve) - 78,000 Units ($4.99)
6. DogFighter (Dark Water Studios, Ltd) - 67,000 Units ($1.50)
7. Frontlines: Fuel of War (THQ) - 53,000 Units ($2.99)
8. Medal of Honor (Electronic Arts) - 52,000 Units ($59.99)
9. Civilization V (2K Games) - 51,000 Units ($49.99)
10. Half-Life (Valve) - 48,000 Units ($4.99)

http://www.gamasutra.com/view/pressreleases/65722/Fallout_New_Vegas_Leads_Digital_PC_Sales.php

I wonder how much royalties does steam take for publishing games there ?

PS. It's crazy that they sold 50k HL1, 115k CS and 78k HL 2 so many years after release

I would imagine about the same or less as retailers.

Full priced games don't seem to have great sales on Steam. I remember hearing Steam has about 70% of the market as well. Explains why developers focus on consoles.

the numbers are actually good for struggling PC

megalol at half-life 1 legs! 12 years of legs...

No one has access to Steam's numbers, so these figures released by fadedlc, are basically just guesstimations.

And games sold on Steam get a straight 60% cut from sales, 3 times more than console games, and half the hassle.

I have trouble to believe that the Steam's sales are so low (they're not really low considering PC games sell for years). When Valve did the Summer Holiday sale, dozens and dozens of games were discounted and amazing deals. Let me tell you the story of developer Introversion:

Introversion is a small indie developer. Having already made 4 games on PC, they tried their fortune on consoles. Their XBLA debut game, Darwinia , was met with much acclaim (80% on Metacritic) but as soon as they checked D 's sales on XBLA, everything changed.
They knew within 1 hour after D 's launch that it was an utter failure. Because of it, they were forced to shut down their office, and sell all their tables and chairs. Introversion was soon going to disappear.
In a last desperate attempt, they turned to Valve. Valve allowed them to join Steam's Summer Sale, and they put an Introversion Pack, which cost $5 and contained all 4 Introversion games over a weekend.
Result? Introversion made 250k in profit and sold 330k copies on Steam in just 2 days, unbelievable considering it was in the middle of a huge Steam sale with far better and bigger deals than Introversion's, and it was in the summer.

Now Introversion has enough money to not only pay their debts, but also enough to pay everything for a full year. All of this from a couple of days on Steam.

I don't believe in the 300K for Las Vegas on Steam alone. Just no way.

Too good to be true for a PC version.

Based on your story, it sounds like Darwinia failed because people didn't want to pay $15 for Darwinia. As you said, people didn't buy it until it was dirt cheap. Maybe it would have been a success from the get go say if it were... $5?

Anyhow, lets not pretend Indie developers haven't had success on XBLA. Some developers have actually been able to create games that appeal to the masses.

None of Introversion's PC games seemed to have bombed, and all of their PC games were also $15 or above at some point, and have been selling for years(their first game, Uplink, is still being sold 9 years after it's release).

Anyway, as I said, I don't believe the sales figures on Steam are so low.

NPD said already that number of games sold digitally in USA>retail sales.

NPD has NW at >100k for October, steam number is Worldwide

Okay I stand corrected. So total PC sales could be nearly 600K worldwide in October alone? That's really really good (and at $40-49 per copy).