Heres the latest deal I got from viarail, seems to be decent:

Wouldn't you love to see Montréal transformed by colourful foliage? Or surprise your family in Nova Scotia with an impromptu visit? Then take advantage of VIA Rail's new fall sale!

You'll save up to 50% when you book long-distance travel in Comfort sleeper class or Comfort class (economy) aboard the Ocean (Montréal-Halifax) or the Chaleur (Montréal-Gaspé).

How to get your discount

This offer is valid on travel completed between September 27 and December 19, 2007 (inclusive). To be eligible, you must purchase before October 31, 2007.
Seems like a good deal to me, $250 return on the train to Halifax from Ottawa, heres the complete list:

Cities Adult regular fare Discounted fare*
Toronto-Halifax $286 $143
Ottawa-Halifax $235 $117.50
Montréal-Halifax $211 $105.50
Québec City (Charny)-Halifax $175 $87.50
Toronto-Moncton $252 $126
Ottawa-Moncton $202 $101
Montréal-Moncton $173 $86.50
Québec City (Charny)-Moncton $136 $68
Toronto-Bathurst $226 $113
Ottawa-Bathurst $178 $89
Montréal-Bathurst $135 $67.50
Québec City (Charny)-Bathurst $101 $50.50
Montréal-Gaspé $168 $84
Québec City (Charny)-Gaspé $123 $61.50
I'm tempted, hope this is good for some of you guys or gals
Sleeper class prices are different, view below for that pricing

Click here to view the details and to book this deal