If you need a handheld, then I reccomend the Pro-97. The Pro-97 will do railroad, aircraft, plus military aircraft as well. The Pro-97 also has alpha tags, so instead of seeing "120.15" pop up for say, ground control, you'll actually see the words "Ground Control" displayed on the scanner. Try it once and you'll be spoiled.
A note though: If you're going to be listening to Motorola trunked systems, steer clear of the Pro-97, as it's not rebanding capable. For EDACS, and conventional frequencies, it rocks on though.
The Pro-528 is a newer scanner, but does not have the features of the 97. The Pro-528 is about like your Pro-94, except it will do LTR trunking, and is rebanding friendly.
Pro-97's are $199.99 when they're not on sale, and $169.99 when they are. I've seen them as low as $149.99. Pro-528's are $169.99 when not on sale, and are occasionally on sale for $149.99, but last Christmas, they were $99.99!!!
Another note: Both of these scanners are computer programmable! That's right, with proper software and the RadioShack programming cable, you'll never have to enter frequencies by hand EVER! You can fully program either one of these handhelds with your home computer, or laptop.
For base model scanners, I would reccomend the Pro-2055 or Pro-433. These are essentially the SAME scanners as the Pro-97 and Pro-528. They're just base/mobile versions. Pro-97 = Pro-2055, and Pro-528 = Pro-433. Here's a kicker though, while the Pro-528 will NOT scan military aircraft, it's brother, the 433 WILL! How odd is that?
Uniden also has some really sweet handheld scanners, such as the BC246T, which is a pint sized scanner that can fit in your shirt pocket! This scanner will scan aircraft, railroads, and military air too (I think), plus it IS rebanding friendly.
Uniden's newest base/mobiles to hit the market are the 996, and BCT15. These are essentially the same scanner, except the 996 is a digital capable scanner, which you may not need. The 996 is about $300 more than the BCT15, which is priced around $200-$250 depending on where you shop. The 996T is cutting edge, and is priced at $520 + or -.
On another note, if you want distance, put your money in a antenna, and not a scanner. A better antenna will bring new life into your Pro-94, and you'll be able to hear things you have been missing. I reccomend a ScanTenna, or Diamond Discone antenna, outside. The higher you go, the more you'll hear. At an average height of 15 or 20', and with decent terrain, you should be able to jerk stuff in from 40 miles away, no problem!