Having used a fair few pairs of rigids, this is what I’ve found.
– Pace RC31. Beautifully light and comfortable. Seeing them flexing as you’re riding is a bit odd but I suppose thats what makes them a bit more comfortable. Unless you’re very lucky, you won’t get any even 2nd hand for your budget though as it seems everyone wants a pair of these now. Regularly go for £100+ used.
– On-One ‘Superlight’ or whatever they’re called. As has been said above, the most bone jarring, un-compliant forks I’ve ever owned. I know they’re rigids but theres rigid and theres rigid. These may as well be made out of solid steel tubes. Awful things – ugly and heavy but cheap.
– Salsa Cromotos. Had a couple of rides on these now after reading the favourable reviews. And they’re lovely. Not quite as comfy as the Pace’s or as light but they’re things of beauty, well priced, a bit of give in them and most importantly for me was that they’re 455mm long (I think) which nicely slackens and raises the front without a load of spacers etc.
The Exotics were an interesting option, especially as the same fork seems to be available badged up as other things (Bontrager, White Bros, Nukeproof, Boardman etc) for twice the price but I’d read some indifferent reviews on them and I really wanted a unicrown style fork.