I am also experiencing this problem.  The laptop (Dell Inspiron 1520) will lock up, with Caps Lock and Scroll Lock LEDs flashing in unison, which I have read indicates a kernel panic.  Once it happened randomly when shutting down, but I can usually reproduce it (though the time span varies) by sending large files over a wireless link with rsync.

I'm running Kubuntu 8.10 (Intrepid) on x64 hardware.  In case it is helpful, I'm including the entire lspci output:

00:00.0 Host bridge: Intel Corporation Mobile PM965/GM965/GL960 Memory Controller Hub (rev 0c)
00:01.0 PCI bridge: Intel Corporation Mobile PM965/GM965/GL960 PCI Express Root Port (rev 0c)
00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #4 (rev 02)
00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #5 (rev 02)
00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #2 (rev 02)
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 (rev 02)
00:1c.1 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 (rev 02)
00:1c.3 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 4 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #3 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev f2)
00:1f.0 ISA bridge: Intel Corporation 82801HEM (ICH8M) LPC Interface Controller (rev 02)
00:1f.1 IDE interface: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) IDE Controller (rev 02)
00:1f.2 IDE interface: Intel Corporation 82801HBM/HEM (ICH8M/ICH8M-E) SATA IDE Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 82801H (ICH8 Family) SMBus Controller (rev 02)
01:00.0 VGA compatible controller: nVidia Corporation GeForce 8600M GT (rev a1)
03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller (rev 05)
03:01.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 22)
03:01.2 System peripheral: Ricoh Co Ltd R5C843 MMC Host Controller (rev 12)
03:01.3 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 12)
03:01.4 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev ff)
0c:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection (rev 61)

Also, lshw says "processor   Intel(R) Core(TM)2 Duo CPU     T7300  @ 2.00GHz".  I am using the NVIDIA drivers, from the package "nvidia-glx-180".

The last few syslog entries before one such panic:

Feb 12 10:59:30 hazuki vmnetBridge: RTM_NEWLINK: name:wlan0 index:4 flags:0x00011043
Feb 12 10:59:30 hazuki vmnetBridge: Can't add interface wlan0 4 (does exist).
Feb 12 11:00:30 hazuki kernel: [ 1616.989338] CE: hpet increasing min_delta_ns to 33750 nsec
Feb 12 11:01:30 hazuki vmnetBridge: RTM_NEWLINK: name:wlan0 index:4 flags:0x00011043
Feb 12 11:01:30 hazuki vmnetBridge: Can't add interface wlan0 4 (does exist).
Feb 12 11:03:30 hazuki vmnetBridge: RTM_NEWLINK: name:wlan0 index:4 flags:0x00011043
Feb 12 11:03:30 hazuki vmnetBridge: Can't add interface wlan0 4 (does exist).
Feb 12 11:05:30 hazuki vmnetBridge: RTM_NEWLINK: name:wlan0 index:4 flags:0x00011043
Feb 12 11:05:30 hazuki vmnetBridge: Can't add interface wlan0 4 (does exist).

The desktop clock showed 11:06 when I returned about 15 minutes later to find it locked up.  I'll test with the ACPI options given above and report back.