In a post on the game's official message board, BioWare's Chris Priestly states, " If you finished ME1 as a high level character you will receive greater bonuses than those who finished at lower levels." Extra money might be one of those bonuses but don't expect a massive advantage. You will also be able play the same character again after you complete Mass Effect 2. And BioWare has already confirmed that, "what you do in Mass Effect 2, will have consequences in Mass Effect 3!" So we suspect that you should keep your ME2 save games for the final chapter in the trilogy.
Gallery: Mass Effect 2 Screenshots