Just booked tix to Iceland for April

- Reykjavík
If you're out before 9am, head to Grái Kötturinn for pancakes, bacon, and strong Icelandic coffee. go see the stage at the Tourist Information Center, where you can pick up maps and brochures, and arrange tours and car rentals if necessary. Nearby are three great sites -- the Settlement Museum, the City Cathedral in Austurvöllur Square, and the Harbor House Museum (Hafnarhús), dedicated to contemporary art. All three open at 10am; if you need to kill time until then, stroll over to Tjörnin Pond and see the enormous 3-D map of Iceland inside Town Hall (Ráðhús).

On weekends, most of Reykjavík's best restaurants are closed for lunch; exceptions, both close to Austurvöllur Square, are Fjalakötturinn and Við Tjörnina. lunch, visit Sægreifinn for lobster soup and a seafood kabob. After lunch, head to the eastern half of the city center and survey Reykjavík's two main shopping streets, Laugavegur and Skólavörðustígur. Nearby is Culture House, with a exhibit of medieval manuscripts.

go into the city's oldest cafe, Mokka Kaffi.Skólavörðustígur leads uphill to Reykjavík's most iconic landmark, Hallgrímskirkja, where you can ascend the elevator for a panoramic view. Don't miss the Einar Jónsson Museum next door, dedicated to Iceland's most renowned sculptor; weekend hours are 2 to 5pm. From here it's a half-hour walk to the National Museum south of Tjörnin Pond.can also catch a bus 14 to Laugardalslaug for a rejuvenating taste of Iceland's geothermal bathing culture.
great expensive dinner at Sjávarkjallarinn (Seafood Cellar), great nightlife and try the 2am hot dog at Bæjarins Bestu with everything on it.

-The Golden Circle
Plenty excursions depart from Reykjavík, but the most popular is the "Golden Circle" tour to Tþingvellir, the historic rift valley where the Icelandic parliament first convened in 930; Geysir, the geothermal hot spot that lent its name to all geysers; and the majestic Gullfoss waterfall. Sign up for an 8-hour bus tour, or for more flexibility, rent a car.

- Hot Springs Tour
The hot springs of Reyjkadalur Valley are inside the scenic Mt. Hengill hiking area, near Hveragerði. You can reach Reyjkadalur on horseback; Eldhestar offers a 9-hour tour from Reykjavík, with 5 or 6 hours in the saddle. (The small, manageable, good-natured Icelandic horse is great for beginners.)
Alternatively, rent a car (probaly most convenient and easiest) for the day and hike the route. The drive is less than an hour one-way, and the hike can be accomplished in as little as 2 1/2 hours round-trip. Don't forget your swimsuit.

- The Blue Lagoon
The Blue Lagoon spa -- built around a blue-green geothermal lake within a jet-black expanse of black lava -- is Iceland's most popular visitor destination. Sign up with tour company Tþingvallaleið for transportation to the lagoon on the way to the airport. Allow 2 hours at the lagoon, more if you plan on spa treatments or eating at the restaurant.

My wife and I are going with another couple the first week of March. We were initially sold on the cheap flight to see the Northern Lights but after looking more into all Iceland has to offer, I'm getting more excited about going to check out the lagoons, glaciers, etc. As someone else mentioned, the TripAdvisor folks recommend you not rent a car in winter. So I started looking into some overnight tours to the South coast and they look good, but I hate the idea of being on someone else's schedule for everything. Plus, you're always around groups of people. Wondering if we should just rent a car in Reykjavik for a day or two so we can drive to the Golden Circle on our own and then maybe look into a tour as well. We only have four days so it's a pretty quick trip. Enjoyed reading this thread for ideas. Anyone that's been over there in winter, I'd like to hear how the experience was... Seems like it would be totally different compared to going in August.

Dive Silfra

You're welcome