I might be able to help, but I can't give you firsthand experience since how I haven't owned any of these cards. So instead of boasting about how good my laptop is(n't) here are the technical specs of the cards you've mentioned in comparison to each other (according to notebookcheck.com)

Intel Graphics Media Accelerator 950

Intel Graphics Media Accelerator 950 is an integrated (onboard) graphic chip on Mobile Intel 945GM chipset. It is a faster clocked version of the GMA 900.

Specifications

performance class: 5
codename: GMA 950
pipelines: 4 pixel-pipelines
clock: chip: 400 MHz
memory: main memory shared
directX: 9c, Shader Model 2.0
features: Transform and Lighting Hardware Support, HDTV Hardware Motion Compensation
manufacturer site: product page
application area: small and light-weight notebooks

Benchmarks

Here you find a list with approximative benchmark values, which can be achieved with this video card. The values can strongly deviate due to different hardware (processor, memory).

3DMark01: 1300 points
3DMark03: 1300 points
3DMark05: 450 points

NVIDIA GeForce Go 6100 / 6150

NVIDIA GeForce Go 6100 / 6150 is the integrated graphic of NVIDIA nForce Go 430 MCP for AMD Turion notebooks. It doesn't have any integrated memory, but uses a part of the mainmemory (up to 128 MB) like the direct competitor Intel GMA 950. Therefore the gaming performance is quite moderate and can only be used for elder games.

Specifications

performance class: 5
series: GeForce Go 6000
clock: Chip: 425 MHz
memory: shared Memory, Turbocache bis 128MB
directX: 9c, Shader Model 3.0
features: PureVideo, HD TV encoder, Windows Vista Premium
manufacturers site: product page
application area: small and light-weight notebooks
other infos: 110nm, onboard integrated on the NVIDIA nForce Go 430 MCP chipset

Benchmarks

Here you find a list with approximative benchmark values, which can be achieved with this video card. The values can strongly deviate due to different hardware (processor, memory).

3DMark01: 4000 points
3DMark03: 1200 points
3DMark05: 630 points

So the win goes to:

luv_da_oc

professionalnet

Intel Graphics Media Accelerator 950

Specifications

Benchmarks

NVIDIA GeForce Go 6100 / 6150

Specifications

Benchmarks

luv_da_oc