You will not rotate like you suggest at all. In most banks, once you are in you won't rotate at all in some business lines like Sales & Trading (Deutsche is the exception here).
You can apply to IB (Financial Institutions, M&A - that stuff), Sales & Trading, other stuff (Risk, Finance), Research (Fixed Income, Equities). That is your lot, and your job comes from the relationships you develop over the summer. Typically you will be on your way in to one exact spot.
Ginetta is talking about IB. There is a wide appreciation for the art of selling people useless tat through powerpoint presentations, understanding how to value a firm and then further understanding how to tell someone it is worth more and succeed in selling them on it. Pricing merger qualities, picking out acquisition targets - that is the stuff the funds like.
From speaking with Ginetta, his experience is that this is the main feed - research guys sometimes move, but they have to be very respected, in the right field and it isn't the main path. Trading similar - you can trade flow. So can a room full of trained monkeys. If you end up being established in the right form of Prop trading, maybe a HF will come in for you (this path is tricky as Prop traders are small in number, technically focused folk - there is also a big capital, credit line vs compensation tradeoff for the trader).
The difference:
IB - doing "Deals". The stuff in B and C in the Wall Street Journal with stuff starting with $bn.
Traders - buying, selling, holding. So many types of things - credit, equities, debt, FX. So many strategies - Correlation, stat arb, flow, merger arb, momentum. So many products - Options, Debt, futures, forwards, CDS. You get a feel for products that interest you.
Sales - getting the deals for the traders to sell stuff, bringing in business
Research - writing about target prices. Valuation of companies, writing, allegedly generating business. talking on CNBC. Not in cahoots with the Traders, as per Spitzer (at least not formally).
Strategists - work sort of nearer the desk analyzing the market as a whole and creating interesting viewpoints, metrics and feeding the desk first, then potentially clients.