Best Deals of the Transfer Window so far

Jack Colback made one of the shortest but toughest moves of the window

Today is Jim White Day - also knows as Transfer Deadline Day - but plenty of deals have already been finalised and Alex Johnson reviews the best deals so far.

It has been a busy summer for Premier League managers as they look to fit the final pieces into their squad's jigsaw.

It may be early days, but here is a look at which deals look the most astute pieces of Premier League business so far.

Diego Costa was brought in by Jose Mourinho to get goals and he has done just that, with two in his first two Premier League games. After Chelsea's title ambitions were derailed last season by mis-firing strikers, Mourinho moved quickly this summer to bring in Costa from Atletico Madrid for 32 million. He may be only two games in, but Costa's pace and power already looks like it will cause headaches for Premier League defenders.

While Costa brings an influx of goals to Stamford Bridge, the acquisition of Cesc Fabregas appears equally as important. The Spanish playmaker has been a standout performer in Chelsea's league start and the combination of Fabregas and Nemanja Matic at the heart of the Blues midfield looks fantastically balanced. Fabregas's creativity and eye for a pass is going to be key if Chelsea are to overcome teams that effectively 'park the bus'. Last season they struggled to break down defences and Fabregas can be the one to pull the strings. He looks the perfect addition to take over Frank Lampard's mantle in the centre of the Chelsea midfield.

Alexis Sanchez may not have had the best start to his Arsenal career, but surely he is among one of the best deals as it was his goal that secured the Gunners a place in the Champions League group stage. The signing of the 35 million Chilean forward generated a real buzz around the Emirates and what a time for Sanchez to get his first goal for Arsenal to book them a prized place among Europe's elite. Sanchez adds real pace to the Gunners front-line and, with Oliver Giroud out injured for the foreseeable future, he is going to play a key role in their attack.

Arsene Wenger uncharacteristically splashed the cash this summer and his two defensive recruits also look good bits of business. Many eyebrows were raised when 16 million was spent on Calum Chambers, but he has looked assured in central defence since joining the Gunners. With the 19-year-old also offering versatility to the club, it is looking like a solid long-term move for Wenger. The manager also brought in Mathieu Debuchy for 12 million from Newcastle and the Frenchman seems to look better in red-and-white than he ever did in black-and-white stripes.

Everton also appear to have made sound recruitment decisions. 28 million for Romelu Lukaku is a lot of money for the Merseyside club, but if he can repeat the 15 goals he got for them on loan last season then it is money well spent. Lukaku is 21 years old and is only going to improve, and Roberto Martinez is a great manager to bring the best out of the dangerous Belgian. At the other end of the age, and financial, scale is Gareth Barry, who arrived on a free transfer. He also had a successful loan at Goodison and Martinez beat off a host of suitors to get his permanent signature. Barry brings fantastic experience to help develop and support the likes of Ross Barkley in the Everton midfield.

Hull City have really boosted their squad this summer and while the signings of Tom Ince and Jake Livermore look exciting, it is the recruitment of Michael Dawson that could prove a master-stroke by Steve Bruce. The centre half might not be the most thrilling capture, but he brings vast Premier League experience after being at Spurs for almost a decade. He made over 300 appearances for Tottenham and proved himself one of the most reliable centre-backs around in England. Dawson will always dig deep and give 100% - such a blood-and-thunder defender is a rare commodity nowadays.

One of the most important factors for any promoted side is who is going to get them goals in the Premier League. Leicester City broke their club record to get Leonardo Ulloa for 8 million from Brighton and fans got an instant glimpse of what he can do when he netted in their opening game. The big Argentine striker averaged a goal every other game in the Championship and his height and physique means he will be a handful in the Premier League. Ulloa has the potential to hit double figures for Leicester, which could be key to them staying in the top flight.

Jack Colback has made a great impact at Newcastle already since his controversial switch from local rivals Sunderland. The 24-year-old's impressive displays for both the Black Cats and Newcastle have seen him called up to the England squad for the first time. Colback was great in midfield for Sunderland in their great escape last season and he offers his boyhood idols versatility across defence and midfield. His signature on a free transfer already looks an astute piece of business by Alan Pardew.

When Mauricio Pochettino was unveiled as Spurs' new boss, many pundits and armchair experts might have expected big spending on big names. He has splashed cash on Ben Davies and Federico Fazio, but it is Eric Dier who has made the biggest impression on the Spurs fans. The England youth international was brought in for 4 million from Sporting Lisbon and looks a bargain after scoring in Tottenham's first two Premier League games. Dier has been a star of the opening weeks and should continue to make quite an impact in England.

At Swansea, Gylfi Sigurdsson looks a sound addition to the squad at the Liberty Stadium. Garry Monk's decision to bring him back to south Wales after a successful loan spell in 2012 looks a smart piece of business and Sigurdsson will excel if allowed to operate in his favourite position behind the striker. The addition of Bafetimbi Gomis could also prove astute. Swansea were willing to pay 10 million for Gomis 12 months ago but Monk secured his signature on a free this summer. Gomis is a proven goalscorer in France and has a career record of a goal every three games. If he finds his scoring boots at the Liberty, he will endear himself massively to the Swansea fans.