That is the 50mm Nikon I have (except for the LOL-hood). I prefer Pentaxes however, I get more contrast and the min focus distance is like half as far.
The T3I has a much smaller mirror than the 5D, so you are in better shape than the list. In terms of Pentax, the 50mm Takumar 1.4 is considered the holy grail of manual focus lenses (apart from Zei$s). You can get a good one on eBay for about $100. On my 5D, the back of the lens hits the mirror if I am shooting at ininity BUT I rarely shoot at inifinity (its not really the point of a 50mm) and I shoot in liveview, so the mirror has already cleared the lens. Your T3i wouldn't have this problem.
Just make sure the lens is m42 and not bayonett (pentax mount). Also, some of the lenses have yellowed so get one that looks clear.
"On the screwmount Pentax lenses, the Pentax SMC 50/1.4 is supposed to be one of the better 50mm lenses in regards to sharpness and bokeh (out of focus rendition) and it can be had for around the price of the Nikon you're looking at. The only issues you may run into with any manual lens is if the mirror will hit the back of the lens at Infinity but this is only an issue for the Canon 5D, 5DMKII and MKIII. Another good site to checkout is
www.keh.com. They can be a little more pricey for the 'darling' vintage lenses but you can get M42 Pentax and Olympus lenses fairly cheap. "
The Takumar 7 and 8 element lenses are better than the newer SMC. I would recommend getting the Takumar that doesn't say SMC on the front element.