Well, I feel like pointing out the obvious here, but then again noone has mentioned it yet, so:
The Serious Sam games clearly fit your description best! Nothing can be more serious. Luckily, any decent computer should have no trouble running them on max settings (maybe aside from SS3, no idea about that).

Mine does you just need a quadcore and semi decent GPU BF3 is core limited not GPU limited (check it there's reviews using the same CPU which show the game is not GPU limited once you reach the 2GB HD6950/560Ti hell there's one out there showing how a Bulldozer can smash the 2700k in that game once you OC it enough)
BF3 is massively multithreaded in fact it's the first game engine to properly use more than 2 cores.

Any opinion on this build that's on sale at Best Buy for $899.99?
Warranty Terms - Parts
1 year
Warranty Terms - Labor
1 year limited
Product Height
15.7"
Product Width
6.7"
Product Weight
18.1 lbs.
Product Depth
16"
Gaming Series
Yes
Processor Brand
Intel®
Processor
Intel® 2nd Generation Core™ i7
Processor Speed
3.4GHz (Turbo Boost up to 3.8GHz)
Cache Memory
8MB on die Level 3
System Memory (RAM)
8GB
System Memory (RAM) Expandable To
16GB
Type of Memory (RAM)
DDR3
Hard Drive Type
SATA (7200 rpm)
Hard Drive Size
750GB
Graphics
NVIDIA GT 520
Video Memory
2GB
Audio
High-definition with 8-channel (7.1) support
Speakers
None
Network Card
Built-in 10/100/1000 Ethernet LAN (RJ-45 connector)
Wireless Networking
None
Recordable DVD Drive
Yes, double-layer DVD±RW/CD-RW
Recordable DVD Drive Speeds
8x DVD+R DL; 8x DVD-R DL; 16x8x16 DVD+RW; 16x6x16 DVD-RW; 5x DVD-RAM; 48x32x48 CD-RW
Direct-Disc Labeling
No
Digital Media Reader or Slots
Yes, digital media card reader
Available Expansion Bays
External: 1 (5.25"); Internal: 1 (3.5")
Available Expansion Slots
2 PCI
USB 2.0 Ports
10 (4 front, 6 rear)
Keyboard Description
USB gaming
Other Control Devices (mouse, etc.)
USB mouse
Operating System Platform
Windows
Operating System
Windows 7 Home Premium
System Version
64-bit
Software Included
Adobe Reader
ENERGY STAR Qualified
No
Best Buy PC App
Yes
HDMI Output
Yes
Blu-ray Player
No
Graphics Chip
NVIDIA
Drive Capacity
750GB
UPC
886227055562

I hate that term: "serious gamer". A "serious gamer" is not one that insists on playing the latest games. A "serious gamer" is one who plays good games no matter how old they are. My rig, as rarely as it is used anymore, is more than suitable for "serious gaming".

But I disgress. I had a friend's copy of BF3 running on my humble quad-core Phenom X4 920 with each core running at 2.8 GHz, 4GB and my HD 4890 and it ran absolutely fluidly on high. It started twitching mildly on Ultra, but it was certainly running over 60fps on high and more than playable on Ultra. I am yet to encounter a game that struggles on this PC.

The CPU is about 100$ more expensive than the i5 2500K, but gives less than 10% better performance in games, even under ideal conditions. The graphics card is useless for gaming, it's the second slowest card of its entire generation. Actually I don't think it makes much sense to put that card in this build because the graphics chip integrated in the CPU probably provides better performance than the dedicated graphics card. There is no information about the mainboard and the PSU, so these are probably cheap parts with very limited upgrade capability. Especially the PSU is probably quite weak since the graphics card doesn't need much power. For serious gaming, you'd want to switch out the graphics card, which probably means switching out the PSU as well. This means that you'll probably have to pay at least 250$ more (or even more, depending on which graphics card you want). You can save some money by choosing an i5 2500 instead, but the build still isn't cheap for the performance it delivers. Apart from all that, the build seems decent, at least it doesn't add any unnecessary fancy stuff to drive the price up.

I still stand by my earlier recommendation though: Start with an i5 2500 CPU (or an i3 2100 if the i5 is too expensive), add an nVidia 560 GTX graphics card (preferably a 560 Ti), and go from there.

Side note: copy/pasted lists with broken formatting are kind of hard to read. If you instead put a link to the offer into your post, then it#s not only easier to read, we'll also be able to check for information on the details.

Agreed, lower the CPU on that spec and up the graphics card. i5 2500 is a really good CPU and then go for a Nvidia 560Ti or ATI Radeon 6850. Most newer games in recommended specs just say any quad core CPU so unless you us some software that will use more than 4 cores you are wasting money, doing things like video encoding would benefit for higher amount of cores.