Heh - I hadn't thought of it in terms of Zeno's Paradox. As you say, a finite subjective time would pass in an infinite objective time. The point about quantum immortality is also interesting - being condemned to live subjectively forever might be hell as you say.
Barrow and Tipler had a theory that you could potentially "live" for (well, calculate for) an infinite subjective time in a finite objective time if the Universe were to undergo a big crunch -- another vision of hell.
It become asymptotically more difficult to extract useful (free) energy as any thermodynamic disequilibrium disappears, and it gets especially tricky after all the black holes have evaporated due to Hawking radiation (after about 10^100 years).