Driving in Sardinia and Spain=GPS Dilemma

Well, since I will be renting a car in both Sardinia and Spain, I did decide to get a portable GPS. Whether to buy a Garmin or a Tomtom? I had posed the question to the LonelyPlanet website with 2 answers(with one "vote" for each), when I headed off to Best Buy to check them out. Marcus, the helpful Best Buy clerk, me swayed me towards the Garmin. Oh, and, it was on sale ($139 vs. regularly $179)!
That was the easy part. THEN I had to get European maps, and Marcus suggested that I buy them on-line. (In retrospect, I'm not sure why he did, but I opted for that. He actually led me to think they did not stock them.)So I brought the GPS home, plugged it into my car, and was pleased with the way it worked, although Marcus had shown it to me.
Ah, that getting the European maps was that easy! Today I went on-line (now armed with a Garmin 10% off coupon from registering the GPS system), and bought the maps. I had three choices-download to my computer, a DVD, which would take 2-3 weeks to ship, and _________?_. I decided-or I thought it would make the most sense-to have these maps on my laptop, but it turned out that it needed SO MUCH SPACE (1907MB vs. 525MB on my laptop) that it could not be downloaded onto my computer. Having it on my laptop would make it better for travelling, in case I wanted to plan routes, etc. I canonly load it onto one computer, so loading it onto the desktop wouldn't work. So BACK TO MARCUS AND BEST BUY, as I was told that a special cable to download data would work. Well, several hours later, I am no closer to the European maps, but I do have more than two months to get them, and I will. Oh, yes, when I was trying to download the maps, somehow the language changed to Spanish! I FINALLY managed to get the device back to English at least. So hopefully I will get some SOLUTION from the Garmin customer service tomorrow. They are very responsive via email; it was a thirty minute wait on the phone!:((