Until Friday all Kalypso published games on Steam are at a discount.

Broken Sword 2: The Smoking Mirror

US: $5.99 $4.49
UK: £3.99 £2.99 (8% higher)
EU: 4,99€ 3,74€ (22% higher)

Broken Sword 3: The Sleeping Dragon

US: $5.99 $4.49
UK: £3.99 £2.99 (8% higher)
EU: 4,99€ 3,74€ (22% higher)

Broken Sword: Twin Pack

US: $9.99 $7.49
UK: £7.98 £5.98 (30% higher)
EU: 8,99€ 6,74€ (32% higher)

Ceville

US: $19.99 $9.99
UK: £19.99 £9.99 (62% higher)
EU: 29,99€ 14,99€ (120% higher)

Commandos 2: Men of Courage

US: $6.99 $5.24
UK: £4.99 £3.74 (16% higher)
EU: 5,99€ 4,49€ (25% higher)

Commandos 3: Destination Berlin

US: $6.99 $5.24
UK: £4.99 £3.74 (16% higher)
EU: 5,99€ 4,49€ (25% higher)

Crash Time 3

US: $19.99 $14.99
UK: £19.99 £14.99 (62% higher)
EU: 29,99€ 22,49€ (120% higher)

Dawn of Magic 2

US: $29.99 $14.99
UK: £29.99 £14.99 (62% higher)
EU: 29,99€ 14,99€ (46% higher)

Grand Ages: Rome

US: $39.99 $19.99
UK: £24.99 £12.49 (1% higher)
EU: 34,99€ 17,49€ (28% higher)

Hired Guns: The Jagged Edge

US: $29.99 $14.99
UK: £24.99 £12.49 (35% higher)
EU: 29,99€ 14,99€ (46% higher)

Imperium Romanum Gold Edition

US: $19.99 $9.99
UK: £14.99 £7.49 (22% higher)
EU: 19,99€ 9,99€ (46% higher)

Officers

US: $29.99 $22.49
UK: £24.99 £18.74 (35% higher)
EU: 29,99€ 22,49€ (46% higher)

Patricians and Merchants

US: $14.99 $10.04
UK: £14.99 £10.04 (62% higher)
EU: 14,99€ 10,04€ (46% higher)

Tropico 3 - Steam Special Edition

US: $39.99 $29.99
UK: £29.99 £22.49 (22% higher)
EU: 39,99€ 29,99€ (46% higher)

Tropico Reloaded

US: $9.99 $4.99
UK: £9.99 £4.99 (62% higher)
EU: 9,99€ 4,99€ (46% higher)

Any of these good? I have Commandos already, but haven't heard of the others.

Ceville was one of the best p&c adventure games of 2009 imo. Too bad it flopped, according to the German developer Realmforge Studios it even sold horrible for an adventure game.
English reviews:
http://www.adventuregamers.com/article/id,990
http://uk.pc.ign.com/articles/967/967223p2.html

Broken Sword 2 is a very good sequel to a classic (strange that Steam doesn't offer the first game).

The Patricians & Merchants pack contains one game I loved and one I liked:
- Patrician III http://uk.pc.ign.com/articles/455/455060p4.html
- Darkstar One http://www.mygamer.com/index.php?page=gameportal&mode=reviews&id=552492

If I were to buy only of of the games under $10 there, which should I get?

Under 10$? Let's see...

Broken Sword: Twin Pack US: $7.49
Ceville US: $9.99
Commandos 2: Men of Courage US: $5.24
Commandos 3: Destination Berlin US: $5.24
Imperium Romanum Gold Edition US: $9.99
Tropico Reloaded US: $4.99

Commandos 2 (tactical game by Pyro Studios) is famous for its difficulty. Don't know if Commandos 3 is hard, as well.

If you don't like point & click adventures, I'd say out of those get Tropico Reloaded.

It contains
Tropico http://www.metacritic.com/games/platforms/pc/tropico
Tropico Paradise Island http://www.metacritic.com/games/platforms/pc/tropicoparadiseisland?q=tropico%202
Tropico 2 http://www.metacritic.com/games/platforms/pc/tropico2piratecove?q=tropico%202

I never played them, but they seem to be very good strategygames/building sims.

Get Commandos. Those games are EPIC. I wish they offered the first Commandos as well.

I'd love to buy Ceville, but it's just a tiny bit too expensive :(

Oh wait, Commandos, I have some of those games, I love those games.
They aren't that hard, very fun though. I'm going to have to find them, buried in a pile of old games back at my parents' house.
So probably going to pick up the twin pack or Ceville, I'll look into them. Thanks for the heads up on this deal Rhonin.