If your looking to use it for both hiking, and road trips, then Garmin offers the most software for either job and in my opinion the best after the purchase service if something goes wrong. There gear is very good. I have the Map60CSX which I really like google it for a review, and I have the Legend 60 C, also color but smaller. The antenna on the 60CSX is far better and you can add and external antenna on it also.. Both these units have all the bells and whistles. I prefer the 60CSX to all of them. The Magellens are decent also and I have one of those in Color in the Marine and land format. Great unit. Magellen has since gone to a rechargable battery which is fine but you need to buy and extra one, so incase it goes dead in the woods you can replace it. I prefer the Garmin method of 2 double A batteries. Easy to carry and you can get the 2600 MA ones that are rechargeable and last a LOOOOOOOOOOOOng time....
Lowrance is a very good GPS also but not as much software to choose from for my taste but they are a nice unit.
If money is no object and top of the line is what you want in both quality and $$$$$$$$ look into the Trimble GPS....They offer a lot but very expensive..... They all do the same thing, all with same accuracy in feet. Antennas are the big deal along with high end receiver chips. The Garmin 60 CSX has that well covered.
As you can see I favor Garmin, mostly because they are trouble free and if there is a problem, they will take care of it fast and above and beyond the call of duty, often just sending you a new unit for free.
If your interested in TOPO only then the there are a few with better mapping on them then the current Garmin TOPO in contour detail but it depends on what your plans are for it..The Garmin topo serves my needs very well. The upper end Garmins have auto routing also with audio if you add the software....Really nice. If for car use, the bigger the screen the better. If its more for road then hiking, then I would go strictly a car GPS as it has a bigger screen and much easier to use.
check with Royal, he just purchased a new one and see his thoughts on the one I suggest. Garmin also has a HCX Vista model also, slightly less money, but smaller in size. I have the same size one in the Legend C but don't carre for the rubber piece around it which would be the same on the HCX. When its hot in the summer, it comes loose. Minor annoyance but still there. The CSX is a larger unit. Google all these and buy all means, if you have time, to a place like Cabelas and hold them your self. See which one fit syour hands and feels better to work the buttons.
George-Ct