Originally Posted by
ILuvParis
The Starwoods and Marriott are all modern convention hotels.
The Renaissance Blackstone, while not the most centrally located (it's near the Hilton), is a Marriott and certainly qualifies as grand old and possibly trendy. The new JW Marriott in the Loop also arguably is both but, again, not an ideal location for a tourist (but not terrible either).
Like you said, the main Marriott on Michigan is in a better location for tourists (with the Ren on Wacker a close second) but they're neither trendy nor grand old, and the Marriott in particular can be convention central.