Casual UR Control Slaver

[Legato2471]

Creatures
4 Goblin Welder
2 Metalworker
1 Darksteel Colossus
1 Pentavus

Instants
4 Thirst for Knowledge
3 Brainstorm
3 Counterspell
3 Fire/Ice
1 Mystical Tutor

Sorceries
2 Fabricate
1 Tinker

Artifacts
3 Lightning Greaves
2 Mindslaver
2 Jester's Cap
2 Crucible of Worlds
2 Thran Dynamo
1 Grim Monolith
1 Mana Vault
1 Sol Ring
1 Lotus Petal   

Lands
4 Seat of the Synod
4 Great Furnace
3 Steam Vents
3 Shivan Reef
3 Darksteel Citadel
1 Islands
1 Mountains
1 Academy Ruins

Tell me what you think and how I can improve this.

[Philatio]

Well, I think it depends on what you want to invest in a casual deck.  A single Tolarian Academy seems like a worthy addition, but if you want to stay truly casual, perhaps not for the cost.

Onslaught fetchlands (polluteded deltas) are what tend to make brainstorm (or sensei's divining top, which I am about to suggest) good because you get shuffles out of them, which you want anyhow, but they get the steam ventst).  If you want budget versions of those, terramorphic expanse from time spiral is a common that fetches basics, but then you'd have to play more basics and less artifact lands, but it does work with crucible well.

Trinket mage fetches artifact lands, and can also get sensei's divining top.  The top can be fun with welder - you activate the ability to draw a card+put it on top of the library, and in respons weld it out for something, and you get the weld+you get to draw a card.  Also Trash for Treasure from Mirrodin and Argivian Reclamation from Weatherlight give you more one-shot welder-type effects (but you can't do the draw-a-card-with-top-trick with them because they are sorceries).

[forests failed you]

Mox Diamond might be spicy in your deck.

And for sure get yourself a strip mine.