Well im new here.. and was searching for the same topic

. That is how I got here...
Now you didnt mention best gps software for what platform
anyhow... I am going from New Jersey (South as North is a seperate state only known by Southern Jerzey Folks) to North Carolina in 2 weeks... and I can do it without a GPS but they are nice....
my bro in law has the built in GPS in his Ferd Expedition... he was using it and it took him partially the wrong way.... so we reported back to the trusty road atlas...
now I have a Compaq iPaq 3850. This does not have the built in CF slot... A friend gave me the Compaq double jacket for it so now I have 2 pcmcia slots and one has a PCMCIA to CF slot adapter in it...
I went to ebay and did some searching on GPS units for CF slots.... found 2 good ones.... Pharos gps and Globalstat
all in all the Pharos was some $$$$ (still cheap @ around $250 without software). Searching

I found a website that was specific for pda's and laptops over in the UK... I was still wanting the Pharos until I read this article...
http://www.pocketgps.co.uk/globalsat-bc307.php
even that guy is impressed.. so some google searching and I still found it pricey... $150-$225... On trusty ebay I bought one and was shipped to my door for $85. That brings up another rant but will keep short.. I am tired of buying stuff on ebay where people are making their money on shipping.... this gps was $65 buy it now with $15.99 shipping and $2.95 mandatory insurance..
HELLO US PRIORITY MAIL ITEMS THIS SMALL AND WEIGHT ARE $3.95 + INSURANCE!!!!! so the dude made $8 off of shipping... anyway it was still cheaper than on the web... and it was new....
so I have my gps and it works... so now I am looking for software...
I have a borrowed copy of MS Streets and Trips 2005 from a friend...
installed it and pocket streets...
now for the gps pocket streets is good because it shows you the map pretty good... however when you save the map on your pc as a pocket map... THE DRIVING ROUTE DISAPPEARS!!!!!!
Now I am waiting on a 1gb sd card so I can install
TOMTOM 3
&
Destinator
(and buy a FM Transmitter to make my iPaq a mp3 player in the car too)
I may be buying TOMTOM 3 as the site I linked above says it is the best out for pda's. Even better than the new TOMTOM 2004
we shall see... but that is my PDA GPS Hardware recommendation and possible software stuff...
also on that site for the PDA they have Speed traps and yellow light software I believe to tell you where they are... that is

if you live in the UK
I dont have the $$$ right now as I have a family and have been buying necessities for the house and more to come.....
also my bro in law has a tablet pc that he loves.... and I just found out that you can buy the MS Streets and Trips 2005 GPS edition that comes with the usb gps unit to which he could use and really like...
my future upgrade to my wifes 1996 gmc jimmy will be a monitor, pc with gps and xbox hookup for my 5 year old... (and ummmmm my.... sel......f....

)
Boy this post will never end!!!!
also I have a truck...
just a little one... and will use the gps once I have good software to map out all of our 4wheelin spots.
also my bro in law has 186 acres in North NY to which we will use it to map out all of his wheelin trails....so I see many uses with this iPaq gps unit.... very small and portable...also good for walking with....
remember one thing... MS ST is based on the PC and it may give good instructions but if you dont have a tablet pc or laptop that you are willing to lug around.. the product is not designed around portability.... hence designator and TOMTOM have gone around and designed from the PocketPC functionality out......