Could go either way. With integrated graphics, it would probably make a good mobile laptop; with a nice dedicated graphics card, it would probably make a good gaming laptop.
Looks like they basically rebranded the XPS M140 as an Inspiron notebook. Which makes sense, seeing as how the M140 was actually a pretty poor choice for gaming.
AMD's releasing its mobile dual-core 64-bit chip (Turion X2) in a couple of weeks (May 9th); expect to see Turion X2 notebooks approximately 1-2 months after that.
Intel's mobile dual-core 64-bit chip (codenamed Merom) doesn't have an...
*ahem* Getting back on topic...
If you want to play Oblivion at decent settings, I'd recommend going for the 7800. The 1400's not a very powerful card, and I doubt it'll handle many games released a year from now.