ZCN.TO follows the S&P TSX Composite index - that is, the 254 largest companies in Canada. The Z means (well.. not 'means' but 'indicates') it's a BMO-run ETF.
XIU.TO is an iShares one, that follows the TSX 60 - that is, the largest 60 companies (overlapping the 254).
Different providers (BMO, iShares, um um um... Oh, Horizons, Vanguard) provide similar products, the only difference being the MER; or sometimes, they track a different index (the Vanguard one tracks the 100 largest, using a FTSE index not an S&P ones - FTSE and S&P are 'index providers' - they just create and maintain an index, in programming they would create the class, and the ETF would be an instance of a class or an object... heh... never mind).
So there are different ETF providers. Just like there are different mutual fund providers (and in bank-run accounts, you can usually only buy that bank's funds - so with my RBC mutual fund TFSA, I can only buy RBC funds). This is not the case with ETFs/brokerages - different type of thing, though the underlying stuff is the same!
For Canadian 'eligible dividends' you get the enhanced dividend tax credit.
http://www.taxtips.ca/dtc/enhanceddtc.htm - basically that the *company* paying the divi has already PAID tax on it - corporation tax. So you don't have to. This doesn't apply in an RRSP or TFSA.
Have a look at CCP's model portfolios. You can knock your own up quite easily. He lists different ETFs and mutual funds. For simplicity you can just go with TD eSeries funds - very low MER, for a fund. If you already have RBC stuff going on, their funds aren't *too* (0.7% MER for the trackers - vs 0.35% for TD eSeries). CIBC ones are 1%.
If you go the ETF route, ZCN.TO - well, here -
http://www.etfs.bmo.com/bmo-etfs/glance?fundId=72048 - 0.15%