You get what you pay for with the Luxemburg. If you are just looking for a clean room to sleep then this hotel is great value. Staff are friendly, breakfast is adequate and the location cannot be beat. Be aware though that in this part of the city it can be noisy at night, so you will need to sleep with the window closed. We travel to Thessaloniki quite often for shopping and the location of this hotel is great - right in the centre of the city. For anyone coming by car there is paid parking in a private lot behind the hotel - 20 Euro for 24 hours. This is cheaper than the open parking lot in the direction of the port. (if you've been to Thessaloniki before by car you will probably understand these directions). The hotel does provide free wifi - it's not the fastest, but sufficient for checking emails.

We stayed in this Hotel for 3 nights .
From the outide the hotel looks perfect , but the rooms are very small , the elevator is a ' mini ' one , but the staff is friendly and location is very good near the sea-side-boulevard and shopping center .... but far from the train-station !
Breakfast is okay but no more .
Only B-and-B but good restaurants and snack-bars nearby .

I second the many other reviews that talk about the location (just far enough from the main street to be quiet; just close enough to it and to the waterfront to be very handy) and the helpful staff. This was my second stay at the Luxembourg having spent a week there in September 2008. The rooms are fine, the bed was a good size if just a trifle hard for my liking. The breakfast is simple, but very nice. My only concern was the lights from the Croatian Consulate building across the side street streaming through my window...the curtains did an OK job but not perfect.
The free Wi-Fi is a great plus and I had no trouble video Skyping colleagues and family back in the USA.
Not the best location for business unless your business is in the center...but excellent in terms of walking around the waterfront, shops, the Byzantine churches, and the old market.

Very nice and reasonably priced hotel in the centre of Thessaloniki.
-Warm room with tasteful decoration
-Comfortable beds with high quality sheets and quilts
-Very clean bathroom
-Quite rooms available in the back ( we had one on the 4th floor)
-Friendly service by all ( reception, maids, breakfast lady)
-Very good and adequate breakfast.... the lady kept refilling the buffet even though we were among the last ( at around 10.00 )
- discount at 24-hour parking at the corner
- price for our double :99euro

all thumbs up!!