I have just learnt that ATI has very poor openGL surport and thats what you need more than anything else with maya.

Spent £1000 on new PC with a ATI HD 5450 in it and have to replace the card already not happy - most nvidia cards surport OG 2.1 - 4 and have used them for years - and going back as soon as poss.

The rest of your PC sounds fine - for starting off in Maya most setups work - just need a good G-card